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I 


LAKES 


OF 


NOETH    AMEEICA 


A   BEADIXG  LESSON 
FOR   STUDENTS   OF   GEOGRAPHY  AND    GEOLOGY 


BY 


ISRAEL   C.  PtUSSELL 

PEOFESSOR  OF  GEOLOGY,  UNIVEKSITV   OF   JIIC  HIGAIT 


/j'S^  ^ 


GINX  .1-  COMPANY 

BOSTON  •  NEW  YORK  •  CHICAGO   •  LONDON 


Copyright,  1885, 

BV 

ISRAEL  C.  RUSSELL 


ALL  BIGHTS  BESEKVED 
36.8 


CI  NX   .V    CnMI'ANy  •  PKm. 
PKIETORS  •  BUSTON  •  U.S.A. 


G 


(o\3 
3\ 


C^6  |0, 


Ann  ARnoR.  Muhioan, 
April  12,  18114. 


GROVE     KARL    GILBERT, 


S.    GEOLOGICAL    SrRVET, 
WASHIXGTO",  D.  C. 


My  Dear  Sir  :  — 

It  is  now  fourteen  years  since  you  first  guided  my  footsteps  to  the  beaches  of  Lake  Bonne- 
ville and  pointed  out  the  striking  contrasts  in  the  sculpturing  of  the  mountains  above  and  below 
the  horizon  to  which  that  ancient  sea  flooded  the  now  desert  valleys  of  Utah.  For  several  years 
after  the  survey  of  Utah's  former  lake  was  comijleted,  you  directed  my  studies  of  the  basins  of 
similar  lakes  in  Nevada,  California,  Oregon,  and  Washington ;  and  through  your  advice  and 
suggestions  I  was  enabled  to  see  many  things  that  otherwise  might  have  escaped  notice. 

While  writing  this  little  book,  which  so  inadequately  describes  some  of  the  most  interesting 
events  in  the  later  geological  history  of  North  America,  I  have  made  more  use  than  I  could  well 
acknowledge  of  your  volume  on  Lake  Bonneville  and  of  your  more  general  discussion  of  the 
Topography  of  Lake  Shores  —  books  that  are  numbered  among  the  classics  of  American  geology. 

As  a  partial  acknowledgment  of  this  accumulated  indebtedness,  I  beg  to  be  allowed  to 
dedicate  this  book  to  you.  ^ 

I  remain,  very  respectfully, 

ISRAEL   C.   RUSSELL. 


PEEFATORY    :N^0TE. 


A  LARGE  portion  of  the  facts  pertaining  to  the  lakes  of  North  America, 
presented  in  this  book,  were  gleaned  by  the  writer  during  thirteen  years' 
geological  work  for  the  National  Government,  and  are  recorded  principal- 
ly in  the  publications  of  the  U.  S.  Geological  Survey.  The  facilities  for 
exploration  afforded  by  my  connection  Avith  Government  surveys  enabled 
me  to  visit  various  parts  of  the  United  States,  inclusive  of  Alaska,  and  to 
observe  many  phases  in  the  topographical  development  of  our  continent. 

The  publications  of  the  U.  S.  Geological  Survey,  and  of  several  State 

surveys,  also  contain  the  records  of  observations  by  others,  relating  to 

the  subject  here  treated,  which  have  been  freely  used.     It  is  hoped  that 

this  popular  presentation  of  a  small  part  of  the  results  of  the   various 

^  surveys  referred  to  will  serve  to  direct  attention  to  the  rich  and  varied 

f^    store  of  information  contained  in  the  reports  of  my  colleagues  and  fellow- 

tj      workers. 

Besides  the  publications  of  official  surveys,  many  papers  relating  to 
the  subject  here  discussed  have  appeared  in  journals,  proceedings  of 
scientific  societies,  etc.,  to  which  references  may  be  found  in  footnotes  in 
this  volume. 

The  origin  of  lake  basins  and  the  history  of  the  great  cycles  in  the 

development  of  the  relief  of  the  land  to  which  they  pertain,  have  been 

discussed  especially  by  Professor  W.  M.  Davis,  of  Harvard  University. 

Professor  Davis  has  also  read  the  manuscript  of  this  book  and  kindly 

given  me  the  benefit  of  his  criticisms  and  suggestions. 

I.  C.  R. 


INTRODUCTION. 


Lakes  have  their  birth  and  death  in  the  topographic  development  of 
the  land.  A  certain  class  form  a  characteristic  feature  of  lands  recently 
elevated  above  the  sea ;  others  belong  with  the  earlier  stages  or  youth  of 
streams ;  while  still  others  appear  during  maturity  or  in  the  old  age 
of  the  rivers  to  which  they  owe  their  origin.  Lakes  of  a  different  type 
are  associated  with  modifications  of  topography  due  to  glacial  and  to 
volcanic  agencies,  and  to  movements  of  elevation  and  depression  in  the 
earth's  crust. 

Lakes,  like  mountains  and  rivers,  have  life  histories  which  exhibit 
varying  stages  from  youth  through  maturity  to  old  age.  The  span  of 
their  existence  varies  as  do  the  lives  of  animals  and  plants.  In  arid 
regions  they  are  frequently  born  of  a  single  shower  and  disappear  as 
quickly  when  the  skies  are  again  bright;  their  brief  existence  may  be 
said  to  resemble  the  lives  of  the  Ephemera.  Again,  the  conditions  are 
such  that  lakes  perhaps  hundreds  of  square  miles  in  area,  are  formed  each 
winter  and  evaporate  to  dryness  during  the  succeeding  sunnner;  these 
may  be  compared  Avith  the  annual  plants,  so  regular  are  their  }ieriods. 
Still  others  exist  for  a  term  of  years  and  only  disappear  during  seasons  of 
exceptional  aridity;  but  the  greater  number  of  iidaiid  water  bodies 
resemble  the  Sequoia,  and  endure  for  centuries  with  but  little  apparent 
change.  So  long-  are  the  lives  of  many  individuals  that  human  history 
has  recorded  only  slight  changes  in  their  outlines,  but  to  the  geologist 
even  these  are  seen  to  be  of  recent  origin  and  the  day  of  their  extinetiou 
not  remote. 

The  tracing  of  the  life  histories  of  lakes  and  the  recognition  of  the 
numerous  agencies  that  vary  their  lives  and  lead  to  their  death,  gives  to 
this  branch  of  physiography  one  of  its  principal  charms. 


Viii  INTi;(JDUCT10N. 

Lakes  are  also  expressive  of  climatic  conditions.  In  humid  regions 
they  usiiall}'  overflow,  are  fresh,  and  vary  but  slightly  in  area  or  in  depth, 
from  season  to  season,  and  from  century  to  century.  In  arid  lands  they 
are  frequently  without  outlets  and  consequently  alkaline  and  saline,  and 
fluctuate  in  sympathy  with  even  the  minor  changes  in  their  climatic 
environment. 

The  history  of  a  lake  begins  with  the  origin  of  its  basin  and  considers 
among  other  subjects  the  movements  of  its  waters,  the  changes  it  pro- 
duces in  the  topography  of  its  shores,  its  relations  to  climate,  its 
geological  functions,  its  connection  with  plant  and  animal  life,  etc.  It  is 
in  this  oreneral  order  that  the  lakes  of  North  America  are  considered  in 
the  present  volume.  The  standpoint  from  which  the  subject  is  treated  is 
that  of  the  geologist  and  geographer,  its  relation  to  man  being  left  to  the 
archaeologist  and  the  historian. 


C  O  ]S^  T  E  X  T  S. 


INTRODUCTION. 

ClIAPTEn    I. 

ORIGIN    OF    LAKE    BASINS. 

PAGE 

Depkessioxs   on  New   Land   Aiseas   .             I 

Basins  due  to  Atmospheric  Agencies       .        ^ o 

"          "      "  Aqieols  Agencies         ..........  y 

"          "      "  Glacial  Agencies 1^ 

"          "      "  Volcanic  Agencies        .         .         .         .         .         •         .         •         •         .  li 

"          "      "  Impact  of  Meteors    .......•••  --^ 

"          "      "  Earthquakes -o 

"          "      "  Organic    Agencies -('* 

"          "      "  Movements  in  the  Earth's  Crust        . 28 

"          "      "  Land-Slides .  01 

"          "      "  Chemical  Action 31 

Conclusion ^"^ 

Chapter    II. 

MOVEMENTS    OF    LAKE    WATERS    AND    THE    GEOLOGICAL    FUNCTIONS 

OF    LAKES. 


Tides "-^ 

Waves  and  Currents  .........•■•'"> 

Seiche       ........••••••••  '^^ 

Temperature        .........•••••  '^'J 

Influence  of  Lakes  on  Climate 3^ 

Influence  of  Lakes  on  the  Flow  of  Streams        .......  •'© 

Lakes  as  Settling  Basins      .......■••••  •'■' 

Mechanical  Sediments        .......•••••  'H 

Chapter  III. 

TOPOGRAPHY  OF  LAKE  SHORES. 

Sea  Cliffs ^'^ 

Terraces      .........••••• 


45 


X  CONTENTS. 

PAGE 

Embankments 46 

Deltas 48 

Ice-built  Walls     ..............     51 

Chapter  IV. 

RELATION    OF    LAKES   TO    CLIMATIC    CONDITIONS. 

Fresh  Lakes. 

Chemical  Composition         ............  55 

Types  of  Fresh  Lakes  .............  57 

The   Laurentian    Lakes     ............  57 

The  U.   S.  Lake  Survey 57 

Chemistry  of  the  Waters  of  the  St.  Lawrence 59 

Erosion  of  Lake  Shores       ............  60 

Commerce  and  Fisheries   ............  61 

Mountain  Lakes. 

Lake  Tahoe 63 

Lake  Chelan       ..............         65 

Saline  Lakes. 

Saline  Lakes  of  Oceanic  Origin 69 

Saline  Lakes  of  Terrestrial  Origin 70 

Chemical  Precipitates  ............  ^1 

Great  Salt  Lake        .............  "^ 

Mono  Lake      ...............  83 

Chapter   Y. 

THE   LIFE    HISTORIES    OF    LAKES. 
Lakes  of  Humid  Regions  ............         90 

Lakes  of  Arid  Regions         .         .         .         .         .         .         .         .         .         .         •         .93 

Chapter  YI. 

STUDIES    OF    SPECIAL   LACUSTRAL    HISTORIES. 

Pleistocene  Lakes  of  the  Laurentian  Basin  .......         96 

Lake  Agassiz  ........  ......  103 

Pleistocene  Lakes  of  the  Great  Basin  ........       106  » 

Lakes  of  the  Remote  Past  ............   114 

Lndex 122 


ILLUSTRATIOl^S. 


Page 

Plate  1.  Ox-bow  Lakes,  Lower  Mississippi 

"  2.  View  of  Stockton  Bar,  L'tah 

"  3.  Map  of  Stockton  Bar,  Utah 1- 

"  4.  Map  of  Gravel  Bar  retaining  Humboldt  Lake,  Nevada      .  .  .14 

"  5.  Map  of  Crater  Lake,  Oregon 2*^ 

"  6.  Sketch  of  Abert  Lake,  Oregon 2() 

"  7.  Chart  of  Laurentian  Lakes,  showing  Prevailing  Cirrents      .         .  ;14 

"  8.  Sea-cliff      in      Boulder     Clay,      South      Manitou      Island,      Lake 

Michigan    ....••••••••  ^^ 

"  9.  Sea-cliff  in  Sandstone,  Av  Train  Island,  Lake  Superior  .  .  .44 

"  10.  Embankment  formed  in  Lake  Bonneville,   Wellsville,  Utah           .  4(5 

"  11.  Gravel  Spit,  Shore  of  Au  Train   Island,    Lake    Superior           .         .  48 

"  12.  A  Recurved  Spit,  Grand  Traverse  Bay,  Michigan     ....  •>() 

"  13.  Sea-cliffs  and  Terraces  formed  on  the  Shore  of  Lake  Bonneville, 

Oquirrh  Range,  Utah      .         .         .       • ^2 

"  14.  Map  of  Saline  and  Alkaline  Lakes  in  the  Arid  Region    .         .         .70 

"  15.  Map  of  Great  Salt  Lake,  Utah,   showing  Changes  in  Area    .         .  78 

"  16.  The  High  Sierra,  from  North  Shore  of  Mono  Lake,    California        .  84 

"  17.  Map  of  Mono  Lake,    California ^^^ 

"  18.  Map  of  Lake   Iroquois ''^ 

"  19.  Map  of  Lakes  Bonneville  and  Lahontan 1"  ' 

"  20.  Tufa  Towers  on  the  Shore  of  Pyramid  Lake,   Nevada        .         .         .  llo 

"  21.  Tufa  Crags,   showing  Successive  Deposits,  Carson  Desert,  Nevada  112 

"  22.  Typical  Specimen  of  Thinolitic  Tufa H*' 

"  23.  Pyramid  Island,  Pyramid  Lake,  Nevada !-'• 

Figure  1.     Cross    Sections     of    the     Canons    of    Canadian    and    Mora    Rivers, 

1  ^ 
New   Mexico ^' 

2.  Profile   of   a   Sea-cliff  and  Terrace 44 

3.  Profile   of   a  Cut-and-Built  Terrace -^-^ 

4.  Sketch  Map  of  an  Embankment ■*' 

5.  Map    of    Sand    Bar    about    the    Head  of   Lake    Superior        .          .  48 

6.  Map   of    Sand   Bar    on    the   South    Shore    of   Lake    Ontario        .          .  49 

7.  Section  , OF    a   Delta        .          .          .          •          •          •          ■          •          •          •  ^ 

8.  Diagram    showing    the    Rise    and   Fall   of   Lake    Lahontan        .          .  1<»8 

9.  Diagram  shoaving  the  Relation  of   the   Terraces  of  Lake  Lahontan 
to  Pyramid  Lake  .  .  •         •         •         •         •  •         •  • 


10 


LAKES   OF  NORTH  AMERICA. 


CHAPTER    I. 

ORIGIN    OF    LAKE    iLiSINS. 

Difficulties  arise  in  classifying  lake  basins,  similar  in  character  to 
those  met  with  when  a  systematic  discussion  of  glaciers,  rivers,  mountains 
and  other  features  of  the  earth's  surface  is  attempted.  That  is,  there  are 
no  natural  groups  separated  by  hard  and  fast  lines,  into  which  they 
naturally  fall.  Certain  types  may  be  selected,  however,  answering  to 
genera  among  plants  and  animals,  about  which  most  lakes  may  l)e 
grouped.  In  selecting  these  types  we  are  guided  by  their  mode  of  origin, 
and  are  thus  led  to  an  incomplete  genetic  classification,  based  on  the 
natural  agencies  which  produce  depressions  in  the  earth's  surface. 

Depi-ossioiis  on  new  land  area.  —  On  lands  recently  elevated  above 
the  sea  or  left  exposed  by  the  evaporation  or  drainage  of  inland  water  bodies, 
there  are  usually  inequalities,  and  water  frequently  collects  in  the  depres- 
sions and  forms  lakes.  There  are  comparatively  few  lakes  of  this  type  in 
North  America,  for  the  reason  that  large  portions  of  our  coasts  are  sinking 
and  new  land  areas  are  rare.  The  lakes  of  Florida.  hoAvever,  are  good 
examples  of  this  class.  They  are  surrounded  l)y  marine  rocks  of  recent 
origin,  and  are  but  slightly  elevated  above  the  sea.  In  fact,  all  of  the 
topographic  features  of  Florida  indicate  immaturity.  The  luxuriant 
vegetation  of  the  southeastern  coastal  plain,  masks  the  slight  inequalities 
of  the  surface,  and,  by  clogging  the  slack  drainage,  leads  to   a   greater 

1  This  subject  has  been  discussed  by  numerous  writers,  and  lias  RmI  to  controversies  not 
yet  ende-d.  The  most  extended  and  most  systematic  treatment  tliat  it  has  received  may 
be  found  in  an  essay  by  W.  M.  Davis  "On  the  classification  of  lake  basins,"  in  Boston 
Soc.  Nat.  Hist.,  Proc,  vol.  21,  1882,  pp.  315-381.  The  mrmerous  references  given  in  this 
paper  constitute  the  best  biblioiiraphy  of  the  subject  available.  An  important  supplementary 
paper  by  the  same  author  is  republished  as  an  appendix  oi  the  present  volume. 


A  LAKES    OF    NOKTH    A.MERICA. 

expansion  of  the  lakes  than  wonkl  appear  if  the  hmcl  was  barren.  The 
wealth  of  vegetation  tends  also  to  preserve  the  original  barriers  from 
erosion.  Abont  the  southern  shore  of  Hudson  bay  there  is  another  area 
recent!}^  abandoned  by  the  sea,  on  which  there  are  lakes,  but  this  region 
is  so  little  known  that  it  cannot  be  pointed  to  with  confidence  as  a  case 
in  point.  In  the  Great  Basin,  as  the  vast  area  of  interior  drainage 
between  the  Sierra  Nevada  and  Rocky  mountains  is  termed,  there  are 
many  lakes,  some  of  them  of  large  size,  which  occupy  depressions  in  the 
surfaces  of  sedimentary  deposits  left  exposed  by  the  evaporation  of  much 
larger  Pleistocene  water  bodies.  Great  Salt  lake  and  Sevier  lake,  Utah, 
occupy  the  lowest  depressions  in  valleys  formerly  flooded  by  the  waters 
of  a  great  inland  sea  to  which  the  name  Lake  Bonneville  has  been 
applied.  Pyramid,  Walker  and  other  lakes  in  Nevada,  occur  in  valleys 
which  are  deeply  filled  with  the  sediment  of  another  ancient  water  body 
named  Lake  Lahontan.  In  these  instances,  however,  and  in  many  others 
of  'similar  character  throughout  the  Arid  Region,  the  positions  of  the 
present  lakes  on  the  approximately  level  floors  of  desert  valleys  have 
been  partially  detennined  by  recent  movements  of  large  blocks  of  the 
earth's  crust  adjacent  to  lines  of  fracture,  and  by  the  unequal  deposition 
of  alluvial  material  swept  out  from  mountain  valleys  and  deposited  on  the 
adjacent  plain.  These  recent  changes  have  modified  the  character  of  the 
basins  now  occupied  by  lakes,  but  essentially  they  are  depressions  on  new 
land  areas,  and  form  the  most  typical  examples  of  their  class  that  can 
be  found  in  this  country. 

There  are  new  land  areas  about  the  borders  of  the  Laurentian  lakes, 
which  have  been  left  exposed  by  the  recession  of  still  greater  lakes  that 
occupied  the  same  basin  at  a  comparatively  recent  date,  and  also  in  the 
region  drained  by  Red  river  in  Minnesota  and  Canada,  formerly  flooded  a 
vast  lake  named  in  honor  of  Louis  Agassiz.  Along  some  of  our  rivers, 
also,  which  flow  through  ancient  valleys  now  deeply  filled,  there  are 
narrow  areas  of  new  land,  similar  to  the  recently  exposed  borders  of  the 
Laurentian  lakes.  In  all  of  these  instances,  however,  the  lakes  formed 
in  the  inequalities  of  the  surface  are  small  and  of  little  importance. 

Lakes  on  new  land  areas  are  surrounded  by  topographic  forms 
expressive  of  youth,  and  are  themselves  evidence  of  topographic  im- 
maturit}'.  When  drainage  is  established  on  such  areas  the  basins  are 
soon  emptied.  The  lives  of  lakes  of  this  class,  as  is  the  case  with  all 
terrestrial  water  bodies,  depend  largely  on  climatic  conditions.  They 
may    continue    longer    in    one    region    than    in    another,    but    in    the 


ORIGIN    OF    LAKE    BASINS.  3 

ordinary  course  of  topographical  development  are  transient  features. 
In  humid  regions  they  are  drained  more  quickly  than  where  the  rainfall 
is  small.  They  are  fresh  or  saline  according  as  they  overflow  or  are 
without  outlet. 

On  old  land  areas  where  the  streams  have 'reached  maturity  or  old 
age,  the  inequalities  of  the  surface  due  to  the  accidents  of  original  depo- 
sition are  removed,  and  lakes  of  the  class  here  considered  are  absent. 
This  is  shown  in  a  striking  manner  by  contrasting  Florida  with  the 
adjacent  Appalachian  region.  In  the  former,  lakes  are  abundant,  and 
their  surroundings  give  abundant  evidence  of  recent  origin  ;  in  the  latter, 
the  topographic  forms  as  well  as  the  terranes  from  which  they  have  been 
carved,  bear  the  stamp  of  antiquity. 

Lands  that  have  been  subjected  to  intense  glaciation,  or  have  re- 
ceived a  covering  of  glacial  deposit,  are  essentially  new  land  area,  and 
bear  evidence  of  topographic  youth  ;  but  the  lakes  characteristic  of  such 
rejuvenated  lands  will  be  considered  in  advance  in  connection  with  other 
results  of  glacial  action. 

Basins  due  to  atmospheric  agencies.  —  The  weathering  of  rock 
surfaces  progresses  unevenly,  on  account  of  varying  hardness  and"  the 
varying  degree  to  which  they  yield  to  chemical  changes.  This  is 
noticeable  particularly  on  granitic  areas,  as  granite  is  especially  prone  to 
disintegration,  and  produces  uneven  surfaces  when  weathered.  The 
tendency  to  decay  unequally,  as  weathering  progresses,  probably  exists 
in  all  rocks  ;  and  it  is  to  be  expected  that  hills  and  hollows  would  result 
for  the  action  of  the  atmosphere  on  any  variety  of  deposit,  especially  if 
marked  variations  occur  in  its  texture  and  composition.  This  tendency  is 
most  easily  detected  when  the  bedding  is  nearly  horizontal,  and  large 
sheets  of  nearly  level  strata  are  exposed  to  the  sky. 

The  products  of  weathering  are  removed  by  water  in  solution  and  in 
suspension,  and  are  l)lown  away  by  the  wind.  When  removed  by  water, 
the  formation  of  basins  is  checked  by  the  cutting  of  outlets.  When 
carried  away  by  the  wind,  depressions  known  as  "  wind-erosion  basins  " 
are  left.^  These  are  basins  of  excavation  or  true  rock  basins,  and  in  this 
respect  resemble  depressions  eroded  by  glaciers.  Some  observers  have 
concluded  that  many  of  the  rock  basins  commonly  ascribed  to  glacial 

1  Numerous  examples  of  shallow,  saucer-shaped  depressions  in  shale,  due  to  the  action 
of  the  wind  on  areas  bare  of  vegetation,  in  the  southeastern  part  of  Colorado,  have  recently- 
been  described  by  G.  K.  Gilbert.     Jour,  of  GeoL,  vol.  3,  1895,  pp.  47-49. 


4  LAKES    OF    NORTH    AMERICA. 

action,  are  wind  erosion  basins  or  areas  of  pronounced  rock  decay,  from 
which  gdaciers  have  removed  the  h)Osened  material  A\ithont  deeply  abraid- 
ing-  the  unweathered  rock  beneath.  The  mode  of  origin  of  rock-basins 
is  still  a  matter  of  controversy,  l)at  it  seems  evident  to  the  writer,  not 
only  from  reading  the  vfirious  views  advanced  by  others,  but  also  from 
personal  observation  in  many  lake  regions,  that  I'ock  basins  have  been 
formed  by  each  of  the  agencies  mentioned  as  well  as  by  a  combination  of 
the  two.  The  formation  of  basins  by  ice  erosion  and  by  chemical  solution 
might  be  included  among  the  results  of  atmospheric  action,  luit  under 
the  classification  here  adopted  they  fall  in  different  categories. 

Atmospheric  agencies  also  lead  to  the  formation  of  basins  liy  depo- 
sition ;  as  for  example,  when  sand  is  drifted  into  dunes.  Drifting  sand 
frequently  travels  across  the  country  for  scores  of  miles  in  the  direction 
of  the  prevailing  Avinds,  and  sometimes  obstructs  valleys  so  as  to  cause 
lakes  to  form.  The  best  illustration  of  this  occurrence  known  to  the 
writer,  is  in  the  central  part  of  the  State  of  Washington.  The  drainage 
of  one  of  the  deep  narrow  valleys  known  locally  as  "  Coulees,"  which 
trench  the  Great  Plain  of  the  Columbia,  lias  been  obstructed  by  immense 
sand  dunes,  so  as  to  form  a  dam  and  retain  the  water  of  Moses  lake.^ 
Below  the  dam  of  drifted  sand  there  are  several  springs  fed  by  lake 
waters  percolating  through  the  obstruction.  These  serve  to  keep  the 
waters  of  the  lake  fresh.  The  springs  below  the  sand  drifts  unite  to  form 
Alkali  creek,  which  in  winter  sometimes  has  sufficient  volume  to  reach 
the  Columbia,  but  in  summer  suffers  from  evaporation,  and  terminates 
in  a  series  of  alkaline  pools. 

Drifting  sand  may  lead  to  the  destruction  of  a  lake  as  is  illustrated 
b}^  an  example  in  western  Nevada.  The  branch  of  Truckee  river, 
supplying  Winnemucca  lake,  is  partially  obstructed  b}'  wind-blown  sand, 
and  a  struggle  for  supremacy  between  the  river  and  the  encroaching 
dunes  is  in  progress.  Should  the  sands  jirevail  and  a  dam  be  formed, 
the  water  supply  of  Winnemucca  lake  would  be  diverted  to  Pyramid 
lake,  and  its  basin  would  soon  become  desiccated. 

Volcanic  dust  is  carried  great  distances  b}-  air  currents,  and  might 
accumulate  in  a  valley  so  as  to  obstruct  its  drainage.  Xo  lakes,  retained 
by  dams  of  this  nature,  are  known  on  tliis  continent,  although  thousands 
of  square  miles  in  the  western  part  of  the  United  States  were  covered,  in 
Pleistocene  and  recent  times,  to  a  depth  of  many  feet  with  fine  volcanic 

1  I.  C.  Russell,  ''Geological  Reconnoissauce  in  Central  Washington,"  U.  S.  Geol.  Surv. 
Bulletin,  Xo.  108. 


ORIGIN    OF    LAKE    BASINS.  5 

deposits,  which  in  some  instances  have  assisted  other  agencies  in  pro- 
ducing inequalities  of  the  surface. 

Basins  due  to  aqueous  ag-encies.  —  In  this  ckiss  of  basins  there  are 
two  important  subdivisions  :  a,  basins  due  to  the  action  of  streams,  and 
b,  basins  due  to  the  action  of  waves  and  currents.  In  eacii  sulnhvision, 
but  more  especially  in  the  first,  there  are  basins  formed  by  excavation 
and  basins  due  to  deposition,  or  basins  due  to  destructive  and  to  construc- 
tive agencies.  Frequently  the  two  processes  have  united  in  tlie  formation 
of  a  single  depression. 

a.  Basins  formed  by  streams.  —  The  drainage  of  new  land  areas,  es- 
pecially in  humid  regions,  soon  obliterates  the  depression  due  to  the 
original  inequalities  of  the  surface,  as  already  explained :  but  other  basins 
resulting  from  the  action  of  the  streams  themselves  are  formed. 

3  When  the  topography  of  a  young  land  area  is  yet  immature,  and  more 
especially  when  the  elevation  is  considerable  and  the  climate  humid,  the 
even  flow  of  the  draining  streams  is  apt  to  be  interrupted  b}^  rapids  and 
water-falls,  at  the  bases  of  which  excavation  is  accelerated  and  depressions 
formed.  The  deepening  of  such  portions  of  stream-lieds.  results  princi- 
pally from  the  friction  on  their  Ijottoms  and  sides,  produced  bv  sand  and 
stones  moved  by  the  swift  currents.  Some  distance  below  falls  and 
rapids,  the  current  usually  slackens,  and  the  waters  deposit  a  portion 
of  their  load.  A  basin  of  this  character  is  now  being  excavated  below 
Niagara  falls,  and  other  examples  may  be  seen  in  the  channels  of  many 
mountain  streams.  Even  on  old  land  areas  like  the  southern  portion  of 
the^Appalachian  region,  where  the  streams  are  engaged  in  cutting  down 
synclinal  table-lands  in  which  hard  and  soft  strata  alternate,  small  basins 
of  the  character  here  referred  to  are  of  common  occurrence,  Shojild  a 
stream  chaniiel  in  which  such  inequalities  have  been  produced  be  aban- 
doned as  a  line  of  drainage,  the  basins  would  be  transformed  into  lakes. 

The  best~example  of  a  lake  l)asin  of  considerable  size  formed  at  the 
base  of  a  water-fall,  that  has  come  under  the  writer's  notice,  is  in  tlie 
Grand  Coulee,  near  Coulee  City,  in  the  State  of  Washington.  The 
Columbia  river  now  skirts  the  northern  and  western  Ijorders  of  the  vast 
lava-covered  region  known  as  the  Great  Plain  of  the  Columbia,  or  more 
familiarly  as  the  "  Big  Bend  country,"  but  in  Pleistocene  times  its  present 
course  was  obstructed  by  glaciers  which  descended  from  the  mountains 
to  the  north,  and  it  was  forced  to  cut  across  the  Big  Bend  through  a 
series  of  deep  canons  in  the  lava.      Its  temporar}^  course  was  through 


b  LAKES    OF    NORTH    AMERICA. 

Grand  Coulee,  and  near  the  present  site  of  Coulee  City,  it  plunged  over 
a  precipice  about  two  hundred  feet  high,  and  formed  a  cataract  of  the 
nature  of  Shoshone  falls,  Idaho,  but  rivaling  Niagara  in  grandeur.  Two 
basins  were  excavated  in  the  rocks  at  the  base  of  the  falls,  which  Avere 
left  as  lakes  when  the  glaciers  retreated  and  the  Columbia  returned  to  its 
old  channel.  •  These  lakes  still  exist  although  desert  shrubs  grow  on  the 
brink  of  the  precipice  over  which  the  waters  of  the  flooded  and  ice-laden 
river  previously  thundered.  Each  of  the  lakes  is  by  estimate  a  mile 
long  and  half  a  mile  broad,  and  of  considerable  depth,  as  is  shown  by  the 
dark  blue  color  of  theij'  waters  when  seen  from  the  crest  of  the  encircling 
cliffs.i 

The. deeper  positions  of  stream  channels  excavated  during  floods,  may 
be  transformed  into  lakes  when  the  waters  subside  or  when  the  course  of 
a  stream  is  changed.  This  is  shown  by  the  temporarj^  ponds  remaining 
in  many  humid  countries  during  droughts  when  water  no  longer  flows 
through  the  customary  surface  channels,  but  is  more  common  in  arid 
ro^ions  where  the  streams  are  subjected  to  still  greater  fluctuations. 

The  basins  just  described  are  formed  principally  by  excavation,  those 
noted  below  are  due  to  deposition. 

In  regions  of  rapid  erosion,  a  high  grade  and  consequently  rapid 
tributary,  may  bring  to. a  sluggish  trunk  stream  more  detritus  than  it  is 
able  to  carry  away.  When  this  ha})pens,  the  main  stream  is  more  or  less 
completely  obstructed,  and  lakes  may  result.  Basins  of  this  nature  occur 
in  the  steep-walled  valleys  of  the  Sierra  Nevada  and  Rocky  mountains, 
and  are  to  be  expected  wherever  streams  have  cut  back  their  trenches  far 
into  an  upland  and  receive  high-grade  tributaries. 

The  alluvial  cones  about  the  bases  of  mountains  in  the  Arid  Region 
are  frequently  several  miles  in  radius,  and  have  a  thickness  near  the 
mouths  of  the  gorges  from  which  the  material  forming  them  was  dis- 
charged, of  two  or  three  thousand  feet  or  more.  When  such  deposits  are 
formed  on  the  opposite  side  of  a  valley  only  a  few  miles  across,  they  may 
unite  one  with  another  so  as  to  form  transverse  ridges  and  give  origin  to 
basins.  Alluvial  cones  are  especially  conspicuous  in  regions  where  the 
drainage  in  the  valleys  is  weak  or  entirely  wanting,  thus  favoring  the 
formation  of  basins  in  the  manner  just  described.  Lake  Tulare,  in 
southern  California,  may  be  cited  as  an  example,  as  it  is  retained  on  a 
broad  alluvial  plain  by  material  swept  out  by  torrents  from  canons  in  the 

1  I.  C.  Kussell,  "Geological  Keconnoissance  in  Central  Washington,"  U.  S.  Geol.  Surv. 
Bulletin,  No.  108. 


ORIGIN    OF    LAKE    BASINS.  7 

Sierra  Nevada.  In  regions  where  the  conditions  are  most  favorable 
for  the  growth  and  preservation  of  allnvial  cones,  there  is  l)ut  little 
rain-fall,  and  the  material  deposited  in  the  vallej^s  is  apt  to  be  porous 
and  of  such  a  character  that  it  absorbs  water  readily ;  for  this  reason 
lakes  may  be  absent  and  the  land  remain  desert-like  and  arid  although 
basins  exist. 

A  lack  of  close  adjustment  in  the  transporting  power  of  streams  may 
sometimes  be  observed  even  in  humid  countries,  and  in  regions  of  mild 
relief.  As  described  by  G.  K.  Warren,^  the  excess  of  material  brought 
by  Chippeway  river  to  the  Mississippi,  obstructs  the  main  stream  so  as 
to  cause  an  expansion  of  its  waters  known  as  Lake  Pepin.  An  approxi- 
mation to  the  same  conditions  occurs  where  Wisconsin  liver  and  Illinois 
river  join  the  "  Father  of  Waters";  but  in  these  instances  it  is  only  in 
the  low  water  stages  that  the  ponding  becomes  conspicuous.  A  tendency 
in  the  same  direction  was  noted  by  J.  W.  Powell  while  making  his  ad- 
venturous journey  through  the  canon  of  the  Colorado  ;  dangerous  rapids 
Avere  encountered  at  localities  where  lateral  streams  had  swept  debris  i'  'o 
the  main  channel. 

Perhaps  the  best  examples  of  lakes  held  by  obstructions  deposited 
by  lateral  streams  that  can  be  cited,  occur  in  valleys  draining  to  the 
Assiniboine,  Manitoba.  The  lakes  referred  to,  are  situated  in  valleys  that 
were  cut  down  to  a  gentle  slope  when  the  abundant  drainage  of  glacial 
lakes  flowed  through  them  ;  l)ut  the  weaker  modern  streams  are  unable 
to  maintain  such  a  faint  ^rade,  and  are  being  silted  up  where  tributaries 
enter.  Long  narrow  lakes  are  thus  formed  above  delta-fans  built  by 
streams  having  a  higher  grade  than  the  main  valley .^ 

The  separation  of  lakes  Brienz  and  Thun,  Switzerland,  has  been  cited 
by  Davis  as  an  example  of  the  partitioning  of  a  valley  by  the  union  of 
deltas  from  opposite  sides.  Interlaken  stands  on  the  beautiful  alluvial 
plain  thus  formed.  Several  other  similar  examples-  in  central  Europe 
have  been  described  by  various  authqj's. 

Lakes  retained  by  the  deposits  of  lateral  streams  and  by  alluvial 
cones,  pertain  to  young  and  immature  streams,  and  are  incident  to  their 
work  of  erosion.  As  topographic  develo[)ment  progresses,  these  water 
bodies  are  obliterated,  but  when  streams  reach  maturity  and  old  age, lakes 
of  another  class  appear  along  their  courses. 

1  Am.  ,Jour.  Sci.,  vol.  Ki,  3d  ser.,  1878,  p.  420. 

2  Warren  Upham,  "  Report  on  Lake  Agassiz,"  Canadian  Geol.  and  Nat.  Hist.  Surv.,  Ann. 
Rep.,  vol.  4,  1888-89,  p.  2'2  B. 


8  LAKES    OF    NOKTH    AMERICA. 

In  the  case  of  mature  streams  that  have  cut  down  the  seaward  portion 
of  their  valleys  nearly  to  base-level,  that  is  approximately  to  the  level  of  the 
ocean,  and  where  rivers  rising  in  mountainous  regions  How  across  low 
plains,  it  frequently  happens  that  the  more  energetic  tributaries  towards 
their  head  waters  bring  in  more  detritus  than  the  gently  flowing  trunk 
streams  are  able  to  carry,  and  deposition  takes  place  on  their  bottoms  and 
over  their  flood  plains.  AVhen  the  main  stream  is  flooded  and  inundates 
its  valley,  its  .load  is  deposited  most  abundantly  on  the  immediate  borders 
of  its  channel,  and  builds  up  lateral  embankments  or  levees.  AVhen  this 
happens,  the  lateral  tributaries  joining  the  main  stream  in  its  lower  coui-se, 
may  not  be  able  to  fill  up  their  valleys  as  rapidly  as  the  borders  of  the 
main  river  are  raised,  and  are  consequently  ponded.  Many  shallow  lakes 
have  been  formed  in  this  manner  along  the  borders  of  the  large  rivers 
flowing  to  the  Gulf  of  Mexico.  The  most  conspicuous  examples  occur 
along  the  banks  of  .Red  river,  Louisiana,  where  lateral  lakes,  as  has  been 
pointed  out  by  Davis,  are  arranged  along  the  side  of  its  levees  like  the 
leaves  on  a  twig. 

In  the  maturity  and  old  age  of  rivers,  when  they  meander  in  broad 
curves  through  a  wide  flood  plain,  as  in  the  case  of  the  lower  Mississippi, 
the  loops  are  frequently  cut  off.  as  shown  on  Plate  1,  and  crescent-shaped 
or  "ox-bow"  lakes  are  left.  Examples  of  lakes  of  this  character  on  a 
small  scale  may  be  seen  along  the  border  of  many  sluggish  brooks  which 
traverse  deeph'  filled  valleys. 

In  the  formation  of  lo^v -grade  deltas,  like  those  now  in  process  of  con- 
stnution  at  the  mouths  of  the  Mississippi,  Nile,  Ganges,  etc.,  the  waters 
break  through  the  levees  of  the  main  stream  during  floods,  and  form 
Inanehing  channels  or  "  distributaries,"  which  in  their  turn  bifurcate  in  a 
similar  manner,  and  buihl  u})  their  channels  and  inundated  borders.  In 
such  instances  low  areas  are  frequently  surrounded  by  embankments,  and 
left  as  basins  containing  shallow  lakes.  ^Nlany  examples  of  this  occur- 
rence are  found  on  the  broad  delta*  of  the  ^Mississippi.  Of  these  Lake 
Pontchartrain  is  the  largest  at  the  present  time.  Lake  Borgne,  in  the 
same  region,  is  another  example,  not  yet  completed.  Tlie  delta  lands  of 
the  Rhine,  in  Holland,  and  of  other  rivers  in  northern  Germany,  contain 
many  lakes  and  swamps  of  the  type  here  considered.  The  celebrated 
Zuyder  Zee  was  formed  in  part  as  a  delta  basin  and  in  part  by  the  con- 
struction of  natural  embankments  adjacent  to  a  low  shore.  Miniature 
illustrations  of  this  method  of  forming  basins  may  be  seen  on  the  deltas 
of  many  small  streams,  l)uilt  in  lakes  and  ponds. 


Lakes  of  North  AjiFEirA. 


OX-BOW    LAKES,    LOWER    MISSISSIPPI. 


ORIGIN    OF    LAKE    BASINS.  9 

The  overloaded  streams  from  glaciers  also  form  levees,  in  much  the 
same  manner  as  in  the  case  of  more  mature  streams.  These  embank- 
ments are  apt  to  be  formed  of  both  coarse  and  fine  material,  and  sometimes 
enclose  low  areas,  so  as  to  obstruct  their  drainage  and  give  origin  to  lakes 
and  ponds.  -Young  streams,  on  account  of  the  amount  of  debris  con- 
tributed to  them,  thus  in  some  instances,  simulate  to  a  certain  degree 
the  behavior  of  more  mature  rivers.  Small  lakes  of  the  class  here  referred 
to  occur  about  the  southern  border  of  the  ^Nlalaspina  glacier,  Alaska. 

h.  Basins  formed  hy  ivaves  and  currents.  —  Basins  are  frequently 
formed  along*  the  ocean's  shore  and  on  the  border  of  lakes,  wliere  sand 
and  gravel  bars  have  been  built  across  the  entrances  of  bays,  or  extend 
from  headland  to  headland  so  as  to  cut  off  a  curve  of  the  shore.  Numer- 
ous examples  of  water  bodies  that  have  been  isolated  in  this  way,  occur 
along  the  Atlantic  coast  and  about  the  shore  of  the  Laurentian  lakes. 
The  history  of  some  of  these  secondary  lakes  may  be  easily  read  from 
the  exceedingly  valuable  series  of  charts  published  by  the  U.  S.  Coast 
and  Geodetic  Survey  and  by  the  U.  S.  Lake  Survey.  It  frequently  hap- 
pens that  lakes  separated  from  the  ocean  by  narrow  sand  bars,  are  fresh. 
This  is  due  to  the  fact  that  the  movement  of  water  through  the  shore 
deposits  is  from  the  land  seaward,  and  the  originally  saline  waters  in  such 
enclosures  have  been  flooded  out.  The  seaward  flow  of  underground 
water  also  explains  why  fresh  water  may  be  obtained  in  wells  on  sand 
bars   of  the   character  here   referred  to. 

Besides  living  examples  of  the  class  of  lakes  here  considered,  there 
are  basins  of  a  similar  origin  still  to  be  seen  about  the  borders  of  lakes 
that  have  ceased  to  exist.  In  the  Great  Basin,  and  especially  on  the 
borders  of  the  valleys  formerly  flooded  by  the  waters  of  lakes  Bonneville 
and  Lahontan,  there  are  small  lakes  and  enclosed  basins  not  now  flooded, 
which  are  due  to  the  formation  of  embankments  about  the  margin  of 
those  ancient  water  bodies.  The  valleys  formerly  covered  with  the 
water  of  these  great  seas  to  the  depth  of  many  hundreds  of  feet  are  now 
for  the  most  part  parched  and  arid,  and  desert  shrubs  cover  the  em- 
bankments of  sand  and  gravel  on  which  the  surf  formerly  broke.  Only 
a  few  of  the  secondary  basins  formed  along  those  ancient  shores  can  be 
referred  to  at  this  time. 

At  the  town  of  Stockton,  Utah,  about  fifteen  miles  south  of  Great  Salt 
lake,  there  is  an  immense  gravel  bar,  formed  near  the  highest  stage  of 
Lake  Bonneville,  which  sweeps  completely  across  the  entrance  of  a  valley 
and  retains  the  waters  drainincj  from  the  southward,  so  a^  to  form  Rush 


10  LAKES    OF    NORTH   AMERICA. 

lake.  This  lake  is  variable  in  area  and  depth.  Sometimes  it  measures 
tAvo  and  one-half  miles  in  breadth  and  is  al)out  five  feet  deep  ;  again, 
dnrino-  seasons  of  nnusual  drought,  it  evaporates  to  dryness.  The  bar 
to  which  it  owes  its  origin  rises  one  hundred  and  fifty  feet  above  its 
surface,  and  under  more  favorable  climatic  conditions  would  retain  a  lake 
many  square  miles  in  area.  The  view  of  the  great  bar  at  Stockton  and 
the  map  of  the  same  locality,  presented  on  Plates  1  and  2,  are  so  graphic 
and  truthful  that  time  need  not  be  taken  to  describe  them. 

Another  example  of  a  lake  basin  formed  by  a  bar  crossing  the  entrance 
of  a  lateral  valley,  is  furnished  by  Lake  Annie,  near  Fort  Bidwell,  Cali- 
fornia. The  ancient  lake  on  the  Ijorder  of  which  the  bar  now  retaining 
Lake  Annie  was  constructed,  flooded  Surprise  valley,  in  the  northeast 
corner  of  California,  during  Pleistocene  times,  but  is  now  represented 
bv  exceedingly  shallow  alkaline  lakes.  Lake  Annie  is  a  few  hundred 
A'ards  in  diameter,  and  is  kept  fresh  and  sweet  by  the  escape  of  its  surplus 
waters  through  the  embankment  retaining  it. 

Perhaps  the  best  of  all  the  examples  of  the  class  of  water  bodies  now 
under  consideration,  that  can  be  referred  to,  is  Humboldt  lake,  Nevada. 
This  lake  occupies  a  secondary  basin  in  one  of  the  valleys  formerly  flooded 
by  the  waters  of  Lake  Lahontan.  When  the  ancient  lake  was  lowered  so 
as  to  approach  extinction,  a  bar  was  formed  directly  across  the  end  of  Hum- 
boldt valley,  where  it  opens  out  onto  the  Carsen  desert.  The  waters  of 
Humboldt  river  were  retained  by  this  bar  when  Lake  Lahontan  fell  so 
as  to  leave  it  dry,  and  a  lake  formed  above  it.  The  waters  escaped  across 
the  bar  and  cut  a  channel,  so  as  to  partially  drain  the  basin  above ;  but  in 
recent  years  an  artificial  drain  has  been  constructed  in  the  opening,  and 
the  lake  now  covers  a  greater  area  than  it  would  had  the  natural  con- 
ditions remained  unmodified.  A  map  of  the  bar  retaining  Humboldt 
lake,  on  which  much  of  the  history  of  its  origin  can  be  read,  is  shown  in 
Plate  4.1 

Basins  due  to  glacial  ag-encies.  —  On  the  surfaces  of  glaciers,  espe- 
cially on  the  lower  portions  of  neve  regions,  there  are  frequently  shallow 
depressions  holding  lakes  which  give  variety  and  an  additional  charm  to 
the  wintry  landscapes  with  which  they  are  surrounded.  Xo  case  is  knoA\'n 
in  which  these  lakes  are  perennial,  although  they  form  in  the  same  locali- 
ties year  after  year.     They  are  of  little  geological  interest,  for  the  reason 

1  I.  C.  Russell,  "Quaternary  History  of  Lake  Lahontan,"  U.  S.  Geol.  Surv.,  Monograph 
No.  11. 


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LlJ  X 


ORIGIN    OF    LAKE   BASINS.  11 

that  they  leave  but  slight  if  any  permanent  records.  Their  waters  are 
so  clear  that  practically  no  sediments  accumulate  in  them.  On  conti- 
nental glaciers,  however,  such  lakes  might  exist  from  year  to  year,  and 
perhaps  receive  sufficient  deposits  to  leave  recognizable  records  after  the 
ice  disappeared.  Certain  deposits  of  exceedingly  fine,  light  colored,  clay- 
like material  termed  loess,  in  the  upper  Mississippi  valley,  are  believed 
by  some  persons  who  have  studied  them,  to  have  been  accumulated 
in  lakes  on  the  surface  of  the  great  ice  sheet  which  formerly  covered 
that  region. 

When  glaciers  flow  through  valleys  surrounded  by  mountains,  they 
sometimes  obstruct  the  drainage  of  lateral  valleys  so  as  to  cause  lakes  to 
form.  The  dams  in  these  instances  are  formed  by  the  ice  in  the  main 
valleys.  The  type  of  this  class  of  lakes  is  furnished  by  ]\liirjelen  lake, 
Switzerland.  In  this  instance  a  lateral  valley  below  the  snow  line  is 
dammed  by  Aletsch  glacier  which  flows  past  its  mouth.  The  lake  is 
variable  in  area,  being  sometimes  a  mile  long  and  at  other  times  completely 
drained  owing  to  the  enlargement  of  the  tunnel  beneath  the  ice  dam 
through  wdiich  it  discharges. 

In  Alaska  there  are  many  lakes  of  the  Miirjelen  type.  About  the 
southern  bases  of  the  foot-hills  of  Mt.  St.  Elias  there  are  several  water- 
bodies  that  are  held  in  check  by  the  jMalaspina  glacier.  The  largest  of 
these,  known  as  Lake  Castani,  at  the  southern  end  of  the  Chaix  hills,  is 
two  or  three  miles  long  and  a  mile  broad  when  at  its  highest  stage,  and 
discharges  through  a  tunnel  eight  or  nine  miles  long,  beneath  the  ice 
sheet  to  the  south.  The  position  of  this  sul>glacial  river  can  be  traced 
by  a  depression  in  the  surface  of  the  ice,  and  when  above  it,  the  muffled 
roar  of  the  imprisoned  flood  can  be  heard  far  below  one's  feet.  Of  many 
lakes  similar  to  Lake  Castani  in  the  same  general  region,  perhaps  the  most 
instructive  is  one  discovered  by  John  Muir,  in  Stikine  valley,  British 
Columbia,  near  the  Alaskan  boundary.  In  this  instance  a  lake  about 
three  miles  long  and  approximately  a  mile  broad,  and  receiving  the  drain- 
age of  five  or  six  residual  glaciers,  is  held  in  a  lateral  valley  by  Toyatte 
or  Dirt  glacier,  which  flows  past  its  entrance.  The  outlet  of  the  lake  is 
through  a  tunnel  in  the  ice,  which  is  sometimes  enlarged  so  as  suddenly  to 
empty  the  basin  and  cause  a  flood  in  Stikine  river. 

The  lakes  formed  when  glaciers  obstruct  the  drainage,  are  variable 
in  size,  owing  to  changes  in  their  draining  tunnels,  and  are  frequently 
emptied,  as  in  instances  just  cited.  The  surfaces  of  these  lakes  are  many 
times  covered  with  floating  ice,  which  is  left  stranded  when  their  waters 


12  LAKES    OF    XORTH    AMERICA. 

escape.  They  are  unusually  turbid  with  silt  brought  to  them  by  glacial 
streams,  and  leave  important  deposits  to  mark  their  sites  when  the  condi- 
tions are  no  longer  favoraljle  to  their  existence. 

The  most  widely  known  example  of  the  formation  of  terraces  about 
the  borders  of  a  glacial-dammed  lake,  is  furnished  by  the  Parallel  Roads 
of  Glen  Roy,  on  the  west  coast  of  Scotland.  The  origin  of  these  terraces 
was  a  fruitful  source  of  controversy  for  many  years  ;  but  the  explanation 
that  they  are  due  to  the  action  of  the  waves  and  currents  of  a  lake  held  in 
a  lateral  valley  by  a  glacier  flowing  past  its  entrance,  has  finally  been 
accepted  as  satisfactory. 

It  is  worthy  of  note,  that  lakes  of  the  type  just  described,  not 
only  occur  in  mountain  valleys,  but  also  about  the  ends  of  mountain  spurs 
projecting  into  encircling  ice  sheets,  as  on  the  northern  border  of  the 
Malaspina  glacier.  The  deltas  and  terraces  formed  in  such  lakes  may 
remain  in  unexpected  places,  as  high  up  on  the  side  of  a  mountain,  whei? 
the  retaining  glacier  is  melted. 

When  the  land  bordering  an  ice  sheet  slopes  towards  the  ice,  the 
escape  of  the  waters  formed  by  the  melting  of  the  glacier,  as  Avell  as 
streams  from  the  adjacent  areas,  is  checked,  and  marginal  lakes,  some- 
times of  large  size,  are  formed.  Two  small  examples  of  this  class  of 
water-bodies  were  seen  by  the  writer  at  the  northern  base  of  the  Chaix 
hills,  Alaska.  During  the  close  of  the  Glacial  epoch,  when  the  ice-sheet 
occupying  northeastern  Xorth  America  was  retreating,  there  came  a  time 
when  the  southern  margin  of  the  ice  faced  a  northAvard-sloping  land- 
surface,  and  lakes  far  larger  than  the  present  Laurentian  lakes,  w^ere 
formed.  The  largest  of  these  ancient  seas,  named  Lake  Agassiz,  covered 
the  reo-ion  in  ^Minnesota  and  Canada  now  drained  bv  Red  river,  and 
others  were  formed  in  the  Laurentian  basin. 

When  glaciers  melt,  the  rock  surfaces  left  exposed  are  frequently 
planed,  grooved  and  polished.  In  such  instances,  the  evidences  of  the 
friction  of  the  flowing  ice  and  of  the  sand  and  pebbles  frozen  into  it,  are 
pronounced  and  unmistakable.  These  marks  of  abrasion  are  frequently 
buried  and  concealed  by  deposits  of  debris  of  various  kinds  which  were 
transported  on  the  surface  of  the  living  glacier  or  enclosed  in  its  mass, 
and  left  as  superficial  deposits  wdien  the  ice  melted.  In  the  lower  por- 
tions of  mountain  valleys  previously  occupied  ])y  ice  streams,  and  over  the 
outer  border  of  regions  formerly  covered  by  continental  ice  sheets,  the 
deposits  of  debris  are  in  many  instances  so  abundant  that  the  worn  rock 
surfaces  beneath  are  completely  concealed. 


Lakes  of  North  America. 


Plate  3. 


MAP  OF  THE  PASS 
between  ■ 

RUSH  AND  TOOELE  VALLEYS.  UTAH. 

sIio\»Tn^  the 

WAVE  BUILT  BARRIER. 

B7    H.   A    Wheeler. 


20  -fttz,   CarvU3uy^ 


Vertical   Section  from   jc   to  Kush    Lake 

Vertji^tiZ-     Soal^      double     tfte     /fortzontaZ^ 


STOCKTON    BAR     UTAH.     (AFTER    GILBERT.) 
Compare  with  Plate  2. 


ORIGIN    OF    LAKE   BASINS.  13 

The  study  both  of  living  glaciers  and  of  the  records  left  by  ancient 
o-laciers  has  proven  that  flowing  ice  both  erodes  and  deposits,  and  that 
basins  result  from  each  of  these  processes. 

Whether  a  glacier  shall  erode  its  beds  or  deposit  material  upon  it, 
seems  to  depend  largely  on  its  grade,  and  consequently  on  its  rate  of 
flow.  In  high-grade  valleys  among  mountains  formerly  occupied  by 
glaciers,  the  higher  and  steeper  portions  of  the  main  avenues  of  ice 
drainage,  are  usually  intensely  glaciated,  and  the  worn  and  rounded 
surfaces  are  frequently  bare  of  glacial  deposits  ;  but  the  lower  portions  of 
such  valleys,  especially  where  they  open  out  on  a  plain,  are  almost  always 
heavily  covered  with  morainal  material.  Not  only  are  moraines  deposited 
in  the  mouth  of  the  valleys,  but  sheets  of  gravel,  clay,  and  boulders  are 
spread  over  the  bottom  of  the  glaciated  troughs,  showing  that  the  ice- 
streams  in  such  situations  deposited  material  on  the  surface  over  which 
they  flowed. 

Above  the  region  of  most  intense  giaciation  in  lofty  mountains  there  is 
a  zone,  embracing  the  higher  summits,  where  polished  and  scratched 
surfaces  are  rare,  and  where  there  is  but  little  debris.  This  upper 
region  was  the  site  of  the  neves  or  snow  fields  of  the  glaciers  that  abraded 
the  rocks  at  a  lower  horizon  and  deposited  their  loads  when  the  grade 
decreased  and  the  ice  currents  were  slackened.  A  similar  association  of 
a  region  of  glacial  alirasion  and  an  outer  zone  of  glacial  deposition,  may 
be  recognized  in  countries  formerly  covered  by  continental  ice  sheets.  In 
the  region  of  most  intense  giaciation,  in  the  case  of  both  Alpine  and 
continental  glaciers,  as  has  been  shown  by  extended  observation,  there 
are  numerous  rock  basins,  the  sides  and  bottoms  of  which  are  polished  and 
striated.  A  large  number  of  lakes  of  this  character  in  the  Cordilleran 
region  have  been  examined  by  the  writer,  and  their  study  left  no  douljt 
that  they  were  due  to  glacial  action.  These  rock  l)asins  are  confined  to 
areas  of  intense  giaciation,  and  are  absent  from  adjacent  areas  where 
the  conditions  are  essentially  the  same,  except  that  glaciers  have  not 
passed  over  them. 

It  is  impossible  to  point  to  examples  where  living  glaciers  are  actually 
engaged  in  wearing  out  rock  basins,  since  their  work  of  abrasion  is  neces- 
sarily concealed ;  neither  is  it  possible  to  satisfactorily  observe  the  process 
by  which  glaciers  polish  and  striate  rock  surfaces,  yet  no  student  of  the 
subject  doubts  that  these  results  are  produced  by  moving  ice  charged  with 
sand  and  gravel.  The  nature  of  the  evidence  leading  to  the  conclusion 
that  many  rock  basins  are  due  to  glacial  abrasion,  is  of  the  same  character 


14  LAKES    OF    XOETH    AMERICA. 

as  the  evidence  from  which  it  is  concluded  that  man}'  smoothed  and  stri- 
ated rock  surfaces  are  due  to  the  same  agency.  The  rock  basins  of  the 
character  here  referred  to,  are  confined  to  regions  of  former  giaciation,  not 
only  in  America  l)ut  on  other  continents,  and  are  wanting  Avhere  other 
evidences  of  ice  action  are  absent.  The  interiors  of  the  basins  themselves 
are  smoothed  and  striated,  and  bear  incontestable  evidence  that  in  part  at 
least,  they  are  due  to  the  abrasion  of  sand-charged  ice.  These  more 
general  considerations  are  in  such  harmony  with  what  is  known  of  the 
work  of  ice  streams,  that  the}'  carry  even  more  weight  than  special 
studies  of  individual  lakes. 

Although  the  evidence  leading  to  the  conclusion  that  many  rock 
basins  in  glaciated  regions  are  essentially  of  glacial  origin,  seems  to  the 
writer  to  be  conclusive,  it  is  but  just  to  state  that,  even  after  thirty  years 
of  ardent  controversy,  there  is  still  a  difference  in  opinion  among  geolo- 
gists and  others,  in  reference  to  the  abrading  power  of  moving  ice,  and  its 
ability  to  erode  rock  basins.  The  literature  bearing  on  this  cpiestion  is  so 
voluminous  that  it  is  impracticable  to  present  even  an  abstract  of  it  at  the 
present  time.^ 

Without  considering  further  the  results  of  the  destructive  action  of 
glaciers,  let  us  see  what  is  the  character  of  the  basin  they  produce  by 
construction.  Fortunately  in  this  connection  there  is  little  difference  of 
opinion. 

The  terminal  moraines  left  by  Alpine  glaciers  in  their  retreat,  fre- 
quently form  crescent-shaped  piles  of  debris,  convex  down  stream,  which 
act  as  dams,  and  retain  lakes.  Hundreds  and  probably  thousands  of 
examples  of  lakes  held  in  check  by  obstructions  of  this  character,  exist  in 
the  valleys  of  the  Cordilleras,  and  are  common  in  every  formerly  glaciated 
mountainous  region.  The  Twin  lakes  in  the  Arkansas  valley,  Colorado,^ 
several  small  lakes  on  the  west  side  of  ^Nlono  valley,  Calif ornia,^  and 
numerous  sheets  of  clear  water  in  the  Wasatch  mountains,  Utah,  so  well 
known  to  tourists,  are  types  of  this  class.     Similar  lakes  occur  about  the 

1  This  subject  has  received  special  attention  since  the  appearance  of  a  celebrated  paper 
by  Ramsay,  "On  the  glacial  origin  of  certain  Swiss  lakes,"  Quar.  Jour.  Geol.  Soc,  vol.  18, 
p.  185  ;  but  a  unanimous  conclusion  has  not  been  reached,  as  may  be  seen  by  consulting 
Nature  for  180.3-9-4.  The  present  status  of  this  interesting  controversy  is  presented  in  a 
paper  by  T.  G.  Bonney,  and  accompanying  discussions,  in  the  Geographical  Journal  of  the 
JRoyal  Geographical  Society,  vol.  1,  1893,  pp.  481-504. 

2  F.  V.  Hayden,  U.  S.  Geol.  and  Geog.  Surv.  of  the  Territories.  Ann.  Kep.,  1874.  pp. 
47-5.3.  J.  J.  Stevenson,  Explorations  and  Surveys  vrest  of  the  lOOth  Meridian  ("  Wheeler 
Survey  "  ).  vol.  3,  1875,  pp.  441-444. 

3  I.  C.  Russell,  U.  S.  Geol.  Surv.,  8th  Ann.  Rep..  1886-87,  PI.  35. 


ORIGIN    OF    LAKE    BASINS.  15 

extremities  of  the  existing  glaciers  of  this  country,  from  the  High  Sierra, 
California,  northward  to  Alaska.  These  are  retained  by  moraines,  from 
which  the  ice  has  receded  within  a  few  years,  thus  leaving  not  even  the 
shadow  of  a  doubt  as  to  their  mode  of  origin. 

Many  of  the  lakes  of  Scandinavia  and  of  Switzerland  are  retained  by 
ancient  moraines,  as  are  also  in  part,  the  long,  deep  lakes  on  the  Italian 
side  of  the  Alps,  and  draining  to  the  Po.  The  most  striking  example  of 
the  type  of  lake  here  described,  however,  which  has  been  studied  by  the 
writer,  is  Lake  Wakatipu,  on  the  east  side  of  the  Southern  Alps,  New 
Zealand.  This  magniticent  water  body,  surrounded  on  all  sides  by  lofty 
snow-clad  peaks,  has  many  of  the  characteristic  features  of  lakes  Como 
and  Maggiore,  and  is  not  second  to  them  in  majesty  and  beauty. 

The  drainage  of  mountain  valleys,  in  which  moraine-dammed  lakes 
have  been  formed,  is  frequently  so  abundant  that  stream  channels  are  cut 
throudi  the  obstructions,  and  the  lakes  drained.  When  this  occurs, 
beautiful  grass-covered  vales  or  "  parks,"  as  they  are  called  in  the  Rocky 
mountains,  are  formed.  These  charming  valleys  are  quite  as  beautiful 
and  frequently  furnish  as  great  a  contrast  to  the  ruggedness  of  the  sur- 
rounding scenery,  as  did  the  gem-like  lakes  that  preceded  them. 

In  most  instances  the  deep  mountain  valleys  of  North  America, 
now  occupied  by  moraine-dammed  lakes,  were  excavated  by  streams 
previous  to  being  glaciated,  and  only  served  temporarily  as  avenues  for 
ice  drainage.  Their  main  topographic  features  are  due  to  stream  erosion 
and  weathering.  Only  minor  changes  such  as  the  smoothing  and  round- 
ing of  their  bottom  contours,  can  be  ascribed  to  glacial  aljrasion. 

The  general  sheets  of  debris  left  after  the  retreat  of  continental  glaciers 
and  by  the  melting  of  the  expanded  extremities  of  large  Alpine  glaciers, 
are  usually  uneven  on  account  of  the  manner  of  their  deposition,  and 
abounds  in  depressions  which  may  hold  water.  In  many  instances  the 
lakes  oriofinatino-  in  this  manner  are  without  surface  outlets,  their  sur- 
plus  water  escaping  by  percolation. 

On  the  formerly  ice-covered  portion  of  northeastern  North  America, 
the  lakes  occupying  depressions  in  the  general  covering  of  superficial 
material  are  so  numerous  that  the  position  of  the  soutliern  boundary  of 
the  old  ice  sheet  may  be  approximately  traced  on  a  drainage  map  of  the 
region  by  noting  the  southern  limit  of  the  lake-strewn  portion.  The  old 
land  surface  south  of  the  glacial  boundary,  is  almost  entirely  free  from 
undrained  basins  ;  and  in  this,  as  well  as  in  other  respects,  presents  a 
striking  contrast  to  the   rejuvenated  surface   of  the   land  to  the  north. 


16  LAKES    OF    NORTH    AMERICA. 

The  lakes  occupying  depressions  on  the  glacial  drift  number  hundreds  of 
thousands.  They  vary  in  size  from  mere  tarns  up  to  splendid  water- 
sheets  many  square  miles  in  area.  In  portions  of  Minnesota,  Michigan, 
and  adjacent  areas,  Avhere  the  drift  is  unusually  deep,  the  lakes  in  irregu- 
lar depressions  on  its  surface  sometimes  numljer  a  score  or  more  to  the 
square  mile.  It  is  estimated  that  in  Minnesota  alone,  there  are  not  less 
than  ten  thousand  lakes  of  this  class,  besides  many  swamps  and  marshes 
marking  the  sites  of  former  lakes  of  the  same  type,  which  have  become 
choked  with  vegetation. 

Numerous  lakes  of  the  same  character  as  those  on  the  drift  of  the  North- 
eastern States  and  Canada,  occur  about  the  southern  margin  of  ]\Ialaspina 
glacier,  Alaska,  in  depressions  in  moraines  left  by  the  retreat  of  the  ice 
within  the  past  few  years.  These  very  modern  basins,  some  of  which  are 
still  occupied  in  part  by  the  ice  of  the  retreating  glaciers,  are  similar  in  every 
way  to  the  basins  on  the  moraine-covered  surfaces  just  referred  to,  and  are 
surrounded  by  topography  of  the  same  character,  thus  leaving  no  room  for 
doubting  that  each  oi  the  two  series  is  due  to  similar  agencies. 

When  the  general  sheet  of  debris  left  after  the  retreat  of  continental 
glaciers  does  not  completely  mask  the  pre-glacial  topograph}-,  former 
vallej's  are  sometimes  dammed,  and  lakes  of  another  type  produced.  In 
many  instances  these  lakes  are  long  and  narrow,  and  indicate,  to  some 
extent,  by  their  form,  the  character  of  the  ancient  drainage  lines  they 
occupy.  Again,  they  may  be  broad  water-bodies,  and  occupy  ancient 
drainao'e  basins,  the  outlets  of  which  have  been  closed.  Pre-glacial 
valleys  may  be  deepened  by  ice  erosions,  as  well  as  obstructed,  and  the 
two  processes  may  unite  to  form  lakes,  as  is  believed  to  have  been  the 
case  in  the  group  of  "  Finger  lakes  "  in  the  central  part  of  New  York  state. ^ 

Still  another  type  of  lake  basins,  due  to  glacial  agencies,  is  found  in 
unconsolidated  water-laid  material  deposited  about  the  borders  of  ice- 
sheets.  When  the  stream-ljorne  debris  from  a  glacier  is  abundant  it 
forms  low  alluvial  cones  and  sand  and  gravel  plains,  which  may  suri'ound 
or  cover  isolated  ice  masses.  Wlien  such  Ijuried  ice  masses  finally  melt 
a  depression  is  left,  and  may  be  water-filled.  The  borders  of  such  lakes 
are  of  loose  material  which  slides  into  the  depression  and  forms  steep 
banks.  The  inclination  of  the  enclosing  walls  depends  upon  the  nature 
of  the  material  of  which  they  are  composed.     Broad  tracts  of  sand  and 

1  A.  p.  Brigham,  "The  Finger  lakes  of  Xew  York."  Geogi-aphical  See.  Am.,  Bull.,  vol. 
25,  1893.  K.  S.  Tarr,  "Lake  Cayuga  a  rock  basiu,"  Geological  Soc.  Am.,  Bull.,  vol.  5,  18Ui, 
pp.  339-356. 


ORIGIN    OF    LAKE    BASINS.  17 

gravel  with  hollows  of  the  character  just  described,  scattered  over  their 
surfaces,  are  known  as  "pitted  plains,"  and  find  their  most  acceptable 
explanation  in  the  hypothesis  just  suggested. 

Lakes  Walden  and  Cochituate,  Massachusetts,  are  believed  to  be 
examples  of  the  class  of  lakes  here  referred  to,  and  to  owe  their  origin  to 
the  melting  of  ice  masses  that  were  either  partially  or  wholly  buried  in 
gravel  and  sand.^  Lakes  of  similar  character  in  southern  Michigan, 
where  glacial  deposits  are  unusually  abundant,  might  also  be  cited  in  this 
connection.  These  lakes  occupy  crater-shaped  depressions  in  the  surfaces 
of  gravel  and  sand  plains,  of  the  character  that  would  be  expected  to 
result  from  the  Inirial  and  subsequent  melting  of  ice  masses,  in  the 
manner  outlined  above. 

From  this  brief  account  of  the  action  of  ice  ^n  obstructing  drainage, 
it  will  appear  that  lake  basins  are  formed  not  only  on  account  of  the 
damming  of  streams  by  the  glaciers  themselves,  but  by  glacial  erosion 
and  glacial  deposition ;  and  in  still  other  ways,  in  connection  with  the 
deposits  made  by  streams. 

Basins  due  to  volcanic  agencies.  —  Inequalities  on  the  surfaces  of 
lava  sheets  sometimes  give  rise  to  lakes  in  much  the  same  manner  as 
lakes  are  formed  on  the  surface  of  glaciers.  Examples  of  such  basins  in 
various  stages  of  extinction,  by  drainage  and  "sedimentation,  occur  on 
portions  of  the  lava  plains  of  Washington  and  Idaho. 

A  lava  stream  may  cross  a  valley  so  as  to  obstruct  its  drainage  and 
cause  a  lake  to  form  a1)ove  it,  in  much  the  same  way  as  glaciers  dam 
lateral  valleys.  A  large  lake  was  formed  in  this  manner,  prolmbly  in 
Pleistocene  times,  on  the  Yukon  river,  Alaska,  where  it  is  joined  by  Pelly 
river.  A  series  of  lava  fioAvs  there  filled  the  river  valley  from  side  to  side 
to  a  depth  of  several  hundred  feet,  and  formed  a  dam  which  retained 
the  waters  of  the  Yukon,  and  gave  origin  to  a  broad  water-body  known 
as  Lake  Yukon.^  The  obstruction  has  since  been  cut  through  along  the 
southern  margin  of  the  old  channel,  leaving  a  series  of  basaltic  precipices 
on  the  right  bank  of  the  river. 

1  Warren  Upham,  Boston  Soc.  Nat.  Hist.,  Proc,  vol.  25,  pp.  228-242. 

2  W.  M.  Dawson,  "  Report  on  an  exploration  in  the  Yukon  district,"  Canadian  Geol. 
Nat.  Hist.  Surv.,  Ann.  Rep.,  1887-88,  p.  132  B. 

I.  C.  Russell,  "Notes  on  the  surface  geology  of  Alaska,"  Geol.  Soc.  Am.,  Bull.  vol.  1, 
1890,  pp.  140-148. 

C.  W.  Hayes,  "An  expedition  through  the  Yukon  district,"  National  Geog.  Mag., 
vol.  4,  1892,  p.  150. 


18  LAKES    OF    NORTH    AMERICA, 

Another  instance  of  the  formation  of  a  lake  on  account  of  the  filling 
of  a  valley  by  a  lava  flow,  but  on  a  much  smaller  scale  than  the  example 
cited  above,  has  been  observed  by  the  writer,  at  the  jiuiction  of  Canadian 
and  Mora  rivers.  New  Mexico.  Canadian  river,  for  a  distance  of  perhaps 
a  hundred  miles,  flows  through  a  steep-walled  gorge,  in  which  for  a  space 
of  several  miles,  near  ^^■llere  Mora  river  joins  it,  there  is  an  inner  gorge, 
as  indicated  in  the  following  cross  section  : 


Fig.  1.  — Cross  Section  of  the  Canons  of  Canadian  and  ISIora  Eia'ers,  New  Mexico 

(j.  j.  stevenson). 

The  valleys  excavated  by  Canadian  and  j\Iora  rivers  were  filled  to  a 
depth  of  400  feet  by  basalt,  as  indicated  by  vertical  lines  in  the  section, 
and  were  subsequently  eroded  to  a  depth  of  230  feet  deeper  than  before 
the  obstruction.  The  lake  which  existed  above  the  lava  flow  has  been 
di-ained,  and  only  indefinite  traces  of  its  former  presence  now  remain. i 

Similar  instances  of  the  damming  of  streams  by  lava  flows,  are  known 
on  the  west  slope  of  the  Sierra  Nevada,  but  are  also  of  ancient  date. 
The  lakes  that  were  formed  have  been  drained,  and  their  bottoms  trans- 
formed into  grassy  valleys. 

Tavo  small  lakes,  held  in  check  by  a  recent  lava  stream,  now  exist  at 
the  Cinder  cone,  near  Lassens  peak,  in  northern  California.  Beneath  the 
lava  retaining  these  lakes  there  is  a  sheet  of  fine  lacustral  marl  and  dia- 
tomaceous  earth,  showing  that  a  former  lake  was  partially  hlled  by  the 
molten  rock,  now  hardened  into  compact  basalt.^ 

Another  class  of  lakes  due  to  volcanic  agencies,  occupy  the  bowls  of 
extinct  craters.  These  occur  in  various  situations,  being  sometimes  at 
the  summits  of  high  volcanic  cones,  and  again  in  depressions  in  broad, 
featureless  plains.  The  walls  enclosing  them  are  sometimes  formed  of 
compact  lava,  but  more  frequently  consist  of  scoria,  lapilli,  and  so-called 
ashes,  blown  out  of  volcanic  vents  during  periods  of  violent  eruption. 

1  This  instructive  locality  has  been  described  by  .J.  J.  Stevenson,  in  Am.  Phil.  Soc,  Proc, 
1880,  pp.  84-87. 

^  J.  S.  Diller.  "  A  Late  Volcanic  Eruption  in  Northern  California."  .U.  S.  Geol.  Surv., 
Bulletin  No.  79,  1891. 


ORIGIN    OF    LAKE    BASINS.  19 

At  Ice  Spring  buttes,  a  group  of  small  volcanic  craters,  near  Fillmore, 
Utah,  there  is  a  pool  of  water  in  the  throat  of  an  extinct  volcano,  which 
occupies  a  depression  formed  by  the  recession  of  the  lava  that  once  rose  in 
and  partially  tilled  the  crater.^ 

The  Soda  ponds  on  the  Carson  desert,  near  Ragtown,  Nevada,  occupy 
lapilli  craters,  the  rims  of  which  rise  20  to  80  feet  above  the  surface  of 
the  adjacent  plain.  The  larger  pond  has  an  area  of  268  acres  and  a 
depth  of  147  feet,  and  its  surface  is  60  feet  below  the  general  level  of 
the  desert.^ 

A  crater  similar  in  character  to  those  holding  the  Soda  ponds,  occurs 
on  one  of  the  islands  in  ]\Iono  lake,  California,  and  is  occupied  by  alkaline 
waters.  The  water  within  the  crater  stands  at  the  same  level  as  the  sur- 
face of  the  surrounding  lake,  a  connection  between  the  two  being  main- 
tained by  percolation  through  the  intervening  embankment  of  incoherent 
lapilli.3 

One  of  the  numerous  craters  near  San  Francisco  peak,  Arizona,  is  said 
to  hold  a  lake  at  a  c(^nsiderable  altitude  above  the  adjacent  country.  In 
the  summit  of  j\It.  Toulca,  Mexico,  a  deep  depression  produced  by  violent 
eruptions  is  stated  by  Davis  to  have  been  similarly  transformed. 

In  many  volcanic  regions  in  other  countries,  lakes  of  this  class  are 
known  to  occur.  They  are  common  in  Italy,  on  North  Island,  New 
Zealand,  and  are  reported  to  occur  in  the  Caucasus,  on  the  Solomon 
Islands,  in  India,  etc.  A  typical  example  of  a  Avater-filled  crater  is  fur- 
nished by  Laacher  See,  on  the  border  of  the  Eifel,  Germany,  and  has  been 
described  and  illustrated  by  Edward  Hull.'* 

Still  another  class  of  lakes  due  to  volcanic  agencies  occur  where  the 
summits  of  volcanoes  have  been  blown  away  by  the  energy  of  the  con- 
fined vapors  within  ;  or  when  the  base  of  a  volcanic  pile  has  been  melted 
so  as  to  cause  it  to  subside  into  the  conduit  from  which  the  material  com- 
posing the  mountain  was  extruded. 

It  is  believed  that  basins  have  resulted  from  each  of  these  processes, 
but  observations  on  their  actual  formation  are  lacking.  It  is  known, 
however,  that  volcanic  mountains  of  large  size  are  sometimes  literally 
blown  away,  as  happened  in  the  case  of  Krakatoa,  in  1886. 

1  G.  K.  Gilbert.     "  Lake  Bonneville."    V.  8.  Geol.  Surv.,  Monograph  Xo.  1,  1890,  p.  322. 

2  1.  C.  Russell.  "Lake  Lahontan."  U.  vS.  Geol.  Surv.,  Monograph  Xo.  11,  1885,  pp. 
72-80. 

3  I.  C.  Russell.  "Quarternary  History  of  Mono  Valley,  California."  U.  S.  Geol.  Surv., 
8th  Ann,  Rep.,  lS8()-87,  p.  873. 

*  "  Volcanoes  :  Past  and  Present."     Contemporary  Science  Series,  pp.  122-123. 


20  LAKES    OF    NORTH    AMERICA. 

In  several  volcanic  regions  there  are  deep,  circular  depressions,  known 
as  "  calderas  "  or  "  crater-rings,"  which  are  believed  to  have  been  formed 
by  the  blowing  away  of  the  mountains  that  once  existed  above  them.  A 
somewhat  complete  series  can  be  established  between  craters  that  have 
been  partially  broken  down  by  subsequent  eruptions,  and  crater-rings, 
about  which  there  are  in  some  instances  no  vestiges  of  the  original  craters 
remaining.  There  is  evidence  also  in  the  character  of  the  rocks  surround- 
ing crater  rings,  and  in  the  adjacent  topography,  which  sustains  the 
hypothesis  of  their  violent  origin. 

Two  of  the  largest  calderas  yet  discovered,  occur  in  Italy,  and  are 
occupied  by  Lago  di  Bracciano  and  Lago  di  Bolsena.  As  described 
by  J.  W.  Judd,  the  first-named  is  nearly  circular,  with  a  diameter  of 
six-and-a-half  miles ;  the  second,  somewhat  less  regular,  has  a  length 
from  north  to  south  of  ten-and-a-quarter  miles,  and  a  breadth  of 
nine  miles.  The  ■  only  examples  of  crater-rings  in  North  America 
that  can  be  referred  to  are  Gustavila  lake,  Mexico,  of  which  the 
writer  has  been  unable  to  obtain  detailed  information,  and  Crater  lake, 
Oregon. 

Crater  lake  has  been  described  by  C.  E.  Dutton,i  and  is  considered  by 
him  as  worthy  of  a  high  rank  among  the  wonders  of  the  world.  It  is 
situated  in  the  Cascade  mountains,  in  n«t4hwestern  Oregon,  thirty  miles 
north  of  Klamath  lake,  at  an  elevation  of  6239  feet  above  the  sea.  It  is 
nearly  circular,  without  bays  or  promontories,  as  indicated  on  the  accom- 
panying map,  Plate  5,  and  is  from  five  to  six  miles  in  diameter.  The 
cliffs  of  dark  basaltic  rock  encircling  it,  rise  precipitously  to  heights  v^ary- 
ing  from  900  to  2200  feet,  and  nowhere  offer  an  easy  means  of  access  to 
the  basin  within.  They  plunge  at  once  into  deep  water,  without  leaving 
even  a  platform  at  the  water's  edge  wide  enough  for  one  to  walk  on. 
There  are  no  streams  tributary  to  the  lake,  and  no  visible  outlet.  The 
waters  probably  escape  by  percolation,  as  the  precipitation  of  the  region 
is  in  excess  of  evaporation,  and  if  an  escape  were  not  furnished  the  basin 
would  be  filled  to  overflowing. 

Near  the  southwest  margin  of  the  lake,  about  half-a-mile  from  shore, 
a  cinder  cone,  named  Wizard  island,  rises  from  the  water  to  a  heiglit  of 
645  feet.  This  cone  is  regular  in  form  and  has  a  depression  in  its  sum- 
mit, thus  showing  at  a  glance  that  it  is  of  volcanic  origin,  and  is  in  fact 
a  miniature  crater  of  eruption.      From  the  base  of  Wizard  island  two 

1  Science,  vol.  7,  1886,  pp.  179-182.  Also,  8th  Ann.  Eep.,  U.  S.  Geol.  Surv.,  1886-87, 
pp.  157-158. 


^^JC^^ 


LAKEiS  OF  XOETH  AMERICA. 

I22°15'  —10' 


423tt 


I22'l3'< 


4/50' 


CRATER   LAKE,    OREGON.     (AFTER  U.  S.  Geological  Survey.) 

Contour-interval  200  feet ;  souudings  in  feet ;  lake  surface  G23y  fetJt  above  sea  level. 


ORIGIN    OF    LAKE    BASINS.  21 

streams  of  hardened  lava  extend  outward  towards  the  great  walls  enclosing 
the  lake,  but  do  not  reach  them. 

The  sounding  line  has  shown  that  Crater  lake  has  a  maximum  depth 
of  2000  feet  and  is  the  deepest  lake  now  known  in  North  America  ;  its 
nearest  rival  being  Lake  Tahoe.  The  full  depth  of  the  basin  measured 
from  the  crest  of  the  enclosing  cliffs,  is  from  2900  to  4200  feet. 

The  rugged  slopes  encircling  the  lake  as  well  as  the  island  that  seem- 
ingly floats  on  its  placid  surface,  are  forest  covered,  thus  softening  and 
rendering  picturesque  the  otherwise  oppressive  grandeur  of  the  scene. 

jNIore  remarkable,  however,  than  the  unique  scenic  features  of  Crater 
lake,  is  the  story  of  its  origin.  The  site  of  the  great  depression  was  once 
occupied  by  a  volcanic  mountain  which  reached  far  above  the  highest 
point  on  the  cliffs  now  enclosing  it,  and  was  probably  as  conspicuous  a 
member  of  the  sisterhood  of  mountains  of  which  it  formed  a  part,  as  any 
of  the  neighboring  peaks,  but  the  once  prominent  pile  lias  been  removed 
so  as  to  leave  the  profound  gulf  that  now  fascinates  and  startles  the 
observer.  The  character  of  the  sculpturing  on  the  outer  slope  of  the 
truncated  mountain  shows  that  it  was  eroded,  both  by  streams  and  by 
glaciers,  before  the  catastrophe  that  carried  away  its  summit  and  left  only 
a  hollow  stump  to  mark  the  site  of  the  ice-crowned  peak  that  formerly 
gleamed  in  the  sky. 

The  removal  of  the  summit  of  the  mountain  is  supposed  to  have  l:)een 
due  to  a  mighty  explosion,  similar  to  that  which  blew  off  5000  feet  from 
Krakatoa ;  or  else  that  the  mountain  was  melted  from  Avithin  and  its 
summit  engulfed  so  as  to  leave  the  depression  now  partially  tilled  with 
placid  waters.  Of  these  two  hypotheses,  the  second  seems  to  accord  best 
with  the  observed  facts,  for  the  reason  that  fragmental  deposits  on  the 
surface  of  the  adjacent  country,  of  the  character  that  would  be  expected 
had  the  summit  of  the  mountain  been  blown  away,  have  not  been  recog- 
nized. Subsequent  to  the  removal  of  the  summit  of  the  mountain, 
renewed  volcanic. energy  of  a  mild  character  built  the  crater-island  within 
the  crater-ring. 

A  circular  depression  in  but  little  disturbed  stratified  rocks  Avhich 
bears  some  resemblance  to  a  crater-ring,  and  which  seems  likely  to  furnish 
the  key  to  the  origin  of  the  calderas  of  Italy  and  other  regions,  has 
recently  been  discovered  in  Arizona,  about  25  miles  southeast  of  the 
town  of  Flagstaff.  This  unique  basin  has  been  carefully  studied  by 
G.  K.  Gilbert,  but  no  account  of  it  from  his  pen  has  come  under  the 
writer's    notice.      The    observations    statied    below    are    mainly  from   a 


22  LAKES    OF    NORTH    AMERICA. 

description    of    a   model    of    the    locality   published    in    the    American 
Geologist.^ 

This  "crater"  in  what  is  known  as  Coon  butte,  is  three-fourths  of  a 
mile  in  diameter  and  its  bottom  is  depressed  from  500  to  600  feet  below 
the  encircling  rim,  which  rises  150  to  200  feet  above  the  surrounding 
plains.  The  surface  limestone  of  the  region,  elsewhere  horizontal,  is 
steeply  inclined  quaquaversally  in  the  cliffs  around  the  crater ;  and 
masses  of  the  same  stratum  and  of  an  underlying  sandstone,  are  strewn 
in  irregular  profusion  outward  from  the  crater  to  the  base  of  the  butte, 
which  has  a  diameter  of  about  two  miles.  In  less  amount,  the  same 
debris  reaches  outward  on  all  sides  over  a  nearly  circular  area  to  a 
distance  of  about  four  miles.  No  lava,  bombs,  lapilli,  or  other  vol- 
canic products,  were  seen.  The  formation  of  this  irregular  crater-like 
depression  is  referred  by  Gilbert,  perhaps  provisionally,  to  a  steam 
explosion. 

The  occurrence  in  the  vicinity  of  Coon  butte  of  hundreds  of  frag- 
ments of  meteoric  iron,  up  to  about  a  pound  in  weight,  and  of  several 
pieces  weighing  from  20  to  600  pounds,  led  at  first  to  the  thought 
that  possibly  a  meteorite  of  great  size  might  have  struck  this  spot,  buried 
itself  out  of  sight  and  thrown  up  a  crater-like  rim.  This  hj-pothesis, 
upon  being  tested,  was  abandoned,  however,  because  the  volume  of  the 
raised  rim  and  of  the  rock  fragments  scattered  about,  was  found  to  corre- 
spond very  closely  with  that  of  the  depression  below  the  level  of  the 
plain  :  and  for  the  second  reason,  that  a  magnetic  survey  failed  to 
indicate  the  existence  of  any  large  mass  of  meteoric  iron  competent  to 
make  such  a  crater,  within  at  least  a  depth  of  many  miles.  This  second 
objection,  however,  is  now  considered  of  but  little  weight,  since  the 
meteoric  fragments  found  about  the  crater,  although  now  magnetic, 
have  undergone  alterations  of  a  character  which  seem  to  indicate  that 
when  they  first  reached  the  earth  they  might  not  have  had  any  or  but 
slight  magnetic  properties.  The  changes  produced  in  the  surface  frag- 
ments are  due  to  atmospheric  influences,  which  would  not  reach  a  deeply 
buried  body. 

The  crater-like  depression  in  the  summit  of  Coon  butte  is  without 
water,  for  the  reason  that  it  is  situated  in  an  arid  region,  but  under 
humid  skies  would  no  doubt  be  transformed  into  a  lake. 

The  only  counterpart  of  Coon  butte  as  yet  discovered,  is  situated  in 
the  central  part  of  the  Peninsula  of  India,  some  200  miles  northeast  of 

1  Vol.  13,  1894,  p.  115. 


ORIGIN    OF    LAKE   BASINS.  23 

Bombay.  This  remarkable  crateriform  lake,  known  as  Lon^s  lake,  is 
described  by  R.  D.  Oldham  ^  as  follows  : 

"  The  surrounding  country  for  hundreds  of  miles  consists  entirely  of 
Deccan  trap,  and  in  this  rock  there  is  a  nearly  circidar  hollow,  about  300 
to  400  feet  deep  and  rather  more  than  a  mile  in  diameter,  containing  at  the 
bottom  a  shallow  lake  of  salt  water  without  any  outlet,  whose  waters 
deposit  crystals  of  sesquicarbonate  of  soda.  The  sides  of  the  hollow  to 
the  north  and  northeast  are  absolutely  level  with  the  surrounding 
country,  while  in  all  other  directions  there  is  a  raised  rim,  never  exceed- 
ing 100  feet  in  height  and  frequentl}'  only  40  or  50,  composed  of  blocks 
of  basalt,  irregularly  piled,  and  precisely  similar  to  the  rock  exposed  on 
the  sides  of  the  hollow.  The  dip  of  the  surrounding  traps  is  always 
from  the  hollow,  but  very  low. 

"It  is  difficult  to  ascribe  this  hollow  to  any  other  cause  than  volcanic 
explosion,  as  no  such  excavation  could  be  produced  l)y  any  known  form 
of  aqueous  denudation,  and  the  raised  rim  of  loose  blocks  around  the  edge 
appears  to  preclude  the  idea  of  a  simple  depression.  It  is  true  that  there 
is  no  sign  of  any  eruption  having  accompanied  the  formation  of  the  crater  ; 
no  dyke  can  be  traced  in  the  surrounding  rocks  ;  no  lava  or  scoriae  of  later 
age  than  the  Deccan  trap  period  can  be  found  in  the  neighborhood.  The 
raised  rim  is  very  small,  and  cannot  contain  a  thousandth  part  of  the  rock 
ejected  from  the  crater,  Ixit  it  is  impossible  to  say  how  much  was  reduced 
to  fine  powder  and  scattered  to  a  distance,  or  removed  by  denudation. 

"  Assuming  that  this  extraordinary  hollow  is  due  to  volcanic  explosions, 
the  date  of  its  origin  still  remains  to  be  determined.  That  this  is  long 
posterior  to  the  epoch  of  the  Deccan  traps  is  manifest,  for  the  hollow 
appears  to  have  been  made  in  the  present  surface  of  the  country,  carved 
out  by  ages  of  denudation  from  the  old  lava  flow.  To  all  appearance 
the  Londs  lake  crater  is  of  comparativeh'  recent  origin,  and  if  so  it 
suggests  that,  in  one  isolated  spot  in  India,  a  singularly  violent  explosive 
action  must  have  taken  place,  unaccompanied  by  the  eruption  of  melted 
rock.  Nothinor  similar  is  known  to  occur  elsewhere  in  the  Indian 
Peninsula." 

Besides  the  obstructions  to  drainage  produced  by  overflows  of  lava, 
and  by  volcanic  explosions,  it  may  also  be  noted  that  volcanic  dust  and 
ashes,  ejected  from  volcanoes  during  times  of  violent  eruptions,  may  br 
deposited  over  the  adjacent  country  in  such  a  manner  as  to  choke  the 
streams  and  possibly  form  dams  which  Avould  retain  lakes.  This  process 
1  "  A  Manual  of  the  Geology  of  India,"'  2d  ed.  Calcutta,  1893,  pp.  19,  20. 


24  LAKES    OF    NORTH    AMERICA. 

has  already  been  referred  to  in  connection  with  the  formation  of  basins 
through  the  action  of  eolian  agencies. 

Lava  streams  frequently  cool  on  the  surface  while  the  liquid  rock  below 
is  still  flowing.  In  such  instances,  when  the  crust  is  sufficiently  strong 
to  sustain  itself,  the  molten  lava  beneath  flows  out,  leaving  caverns. 
Openings  of  this  nature  may  become  water-filled  and  form  subterranean 
lakes,  or  their  roofs  may  fall  in,  leaving  depressions  open  to  the  sky. 
Lakes  and  ponds  occupying  such  depressions  are  thought  to  exist  on  the 
vast  lava  sheets  of  Oregon,  Washington  and  Idaho,  but  clear,  simple 
examples  of  the  type  are  not  at  hand. 

On  a  small  lava  flow  on  an  island  in  ]Mono  lake,  California,  there  are 
depressions  occupied  in  part  by  water,  which  are  due  to  a  general  sub- 
sidence of  the  surface  on  account  of  the  outflow  of  molten  rock  below  aifd 
the  crumpling  of  the  crust  into  concentric,  crescent-shaped  ridges. 

Another  mode  in  which  volcanic  agencies  may  produce  depressions  is 
by  subsidence  of  the  surface  about  volcanoes,  due  to  the  removal  of  lava 
from  subterranean  reservoirs,  but  no  instances  where  this  has  certainly 
occurred  have  yet  been  observed  in  this  country. 

Basins  due  to  the  impact  of  meteors.  —  The  study  of  the  origin  of 
the  crater-like  forms  on  the  surface  of  the  moon  recently  made  by  Gilbert,^ 
was  suggested  by  the  hypothesis  that  depressions  on  the  earth's  surface 
might  result  from  the  impact  of  meteoric  bodies.  This  suggestion  has 
already  been  referred  to  in  describing  Coon  butte,  and  is  one  of  great 
interest.  Up  to  the  present  time,  however,  no  basins  on  the  earth's  sur- 
face ai-e  known  which  can  be  ascribed  to  this  agency. 

If  the  earth  was  formed  by  the  coming  together  of  a  large  number  of 
previously  independent  meteoric  bodies,  as  is  thought  to  have  been  the 
case  by  Lockyer,  all  evidence  of  such  an  occurrence  in  the  relief  of  its 
surface  is  wanting.  Small  meteors  are  known  to  reach  the  earth  every 
day,  and  a  number  have  been  discovered  weighing  many  tons,  but  such 
an  event  as  the  earth  coming  in  contact  with  a  planetary  mass  a  mile  or 
several  miles  in  diameter,  as  seems  to  have  happened  in  the  case  of  the 
moon,  is  not  only  unrecorded  in  history,  but,  as  just  stated,  there  is  no 
evidence  in  the  surface  features  of  the  earth  to  show  that  such  an 
event  has  happened  in  recent  geological  time.  If  the  earth  once  had 
a   pitted   surface,    like    the   moon,   and  was  scarred   by  vast  crater-like 

1  "  The  Moon's  Face,"'  Philosophical  Society  of  Washington,  Bull.  vol.  12,  1893,  pp. 
241-292. 


ORIGIN    OF    LAKE    BASINS.  25 

depressions,  each  one  the  record  of  the  piercing  of  its  surface  and  the 
burial  witliin  its  crust  of  a  planetary  mass  previously  revolving  independ- 
ently in  space,  the  date  of  the  last  of  the  catastrophes  which  produced 
that  condition  must  have  been  so  remote  that  erosion  has  removed  all 
surface  evidence  of  the  fact.  Still  farther  negative  evidence  may  be  cited, 
inasmuch  as  no  buried  meteoric  masses  recognized  as  such,  have  been 
found  in  the  rocks  now  forming  the  earth's  surface.  This  is  not  proof, 
however,  that  the  meteoric  hypothesis,  as  applied  to  the  earth,  is  not  true, 
as  the  main  events  in  that  drama  are  assumed  to  have  been  enacted  before 
the  formation  of  the  stratified  rocks  now  recognizable. 

Basins  due  to  earthquakes.  —  During  earthquakes  there  are  undula- 
tions of  the  surface  of  the  regions  affected  which  sometimes  produce  x>er- 
manent  elevations  and  depressions  and  thus  affect  the  drainage.  The 
passage  of  earthquake  waves  through  loose  deposits  may  cause  them  to 
become  more  compact  and  perhaps  produce  depressions  on  their  surfaces. 
In  these  and  probably  other  ways,  basins  may  be  formed  by  earthquakes 
and  give  origin  to  lakes. 

The  best  examples  of  lake  basins  in  America,  resulting  directly  from 
earthquake  shocks,  occur  in  what  is  known  as  the  "  Sunk  country "  in 
southeastern  Missouri  and  northeastern  Arkansas.  A  series  of  severe 
disturbances,  known  as  the  New  Madrid  earthquake,  affected  that  region 
between  1811  and  1813,  and  caused  both  elevations  and  depressions  in 
the  forest-covered  flood  plain  of  the  Mississippi.  This  region  has  recently 
been  examined  by  W  J  McGee,i  who  reports  that  a  low  dome  some  20  miles 
in  diameter,  was  upheaved  athwart  the  course  of  the  Mississippi  and  that 
the  river  was  held  in  check  for  a  brief  period,  but  soon  cut  a  channel 
through  the  obstruction.  An  adjacent  area  some  one  hundred  square 
miles  in  area,  was  depressed  and  is  still,  in  part,  occupied  by  lakes  in  which 
the  trunks  of  trees  killed  by  the  inundation  are  standing. 

During  earthquakes  iu  regions  occupied  by  unconsolidated  rocks, 
water  is  sometimes  forced  to  the  surface  with  great  violence,  probably  on 
account  of  the  compression  of  porous,  water-charged  strata,  and  rises 
fountain-like  above  the  surface.  The  water  brings  with  it  quantities 
of  sand  and  mud  which  are  deposited  around  the  points  of  discharge  and 
serve  to  enlarge  the  depressions  produced  by  the  violent  outrush.  When 
the  fountains  cease  to  play  these  small  crater-like  basins  remain  as  ponds. 

1  "A  Fossil  Earthquake,"  in  Geol.  Soc.  Am.,  Bull.,  vol.  4,  pp.  411-415. 


26  LAKES    OF    NORTH    AMERICA. 

Basins  due  to  org-anic  ag-encies.  —  The  study  of  coral  reefs  has 
shown  that  bodies  of  sea  water  are  sometimes  cut  off  from  the  ocean, 
although  rarely  completely  separated,  by  the  groAvth  of  reefs  of 
living  coral  adjacent  to  coasts,  or  as  atolls  about  isolated  islands  and 
"  banks."  Lakes  of  this  nature  perhaps  occur  at  the  south  end  of  Florida, 
and  on  the  West  India  islands,  but  no  well  defined  instances  have  been 
described. 

The  formation  of  peat  in  temperate  latitudes  rffords  another  illustra- 
tion of  the  manner  in  which  organic  agencies  lead  to  the  formation  of 
lakes.  The  growth  of  the  moss  known  as  Sphagnum,  from  which  peat  is 
largely  formed,  may  obstruct  sluggish  drainage  ;  and  its  unequal  growth 
in  swampy  areas  leads  to  the  formation  of  mounds  with  depressions  in 
their  sununits.  The  best  known  illustration  of  this  type  is  Drummond 
lake,  in  Virginia,  but  many  smaller  examples  occur  in  other  swampy 
areas.  It,  has  been  suggested  that  the  basins  in  peat  swamps  ma}^  have 
originated  by  the  burning  of  the  bogs  during  times  of  excessive  drouth. 
That  this  might  happen  is  evident,  but  no  authentic  case  of  such  an 
occurrence  is  known  to  the  writer. 

On  the  vast  tundras  skirting  the  Arctic  ocean  in  both  the  Old  and 
the  New  World,  there  are  vast  numbers''  of  ponds  and  lakes  held  in 
depressions  in  the  frozen  l^ogs,  and  surrounded  by  banks  of  moss  and 
other  vegetation.  These  water-bodies  have  probal^ly  originated  in  various 
ways,  but  in  some  instances  their  birth  may  be  traced  to  the  luxuriant 
growth  of  vegetation  in  spring  and  early  summer  about  the  borders  of 
lingering  snow  banks.  When  the  vegetation  of  the  tundras  awakens 
after  its  long  winter  sleep,  its  growth  is  surprisingly  rapid,  and  the  snow 
drifts  that  last  longest  are  surrounded  with  luxuriant  mosses  and  brilliant 
flowers.  When  such  accumulations  of  snow  finally  melt,  the  vegetation 
on  the  areas  they  occupied  is  less  in  amount  than  on  the  surrounding 
surfaces.  The  tundra  increases  in  depth  by  the  partial  decay  and 
freezing  of  the  lower  portion  of  the  vegetation  forming  its  surface,  and 
the  greatest  thickness  of  frozen  soil  occurs  where  the  vegetation  is  most 
luxuriant.  For  these  reasons,  the  places  where  snow  banks  form  year 
after  year,  become  depressed  in  reference  to  the  general  surface,  and  give 
origin  to  lakes. 

In  sub- Arctic  regions,  as  on  the  Aleutian  islands,  mosses  and 
herbaceous  vegetation  grow  luxuriantly,  and  among  the  hills  sometimes 
obstructs  the  drainage  by  reason  of  the  formation  of  a  deep  peaty  soil  by 
its  partial  decay. 


I       ^: 


ORIGIN    OF    LAKE    BASINS.  27 

Beaver  clams  afford  still  another  illustration  of  the  manner  in  which 
drainage  is  obstructed  and  lakes  formed  by  organic  agencies.  Beavers 
formerly  lived  over  nearly  the  whole  of  North  America,  and  are  still 
found  in  limited  numbers  in  the  Northern  states  and  Canada,  and  extend- 
ing southward  along  the  Cordilleras  at  least  as  far  as  New  jNlexico.  The 
dams  they  constructed  with  great  intelligence  and  skill,  across  small 
streams,  retained  drift  logs  and  floating  leaves,  thus  leading  to  the 
accumulation  of  deposits  which  obstructed  the  drainage  for  a  long  time 
after  they  had  been  abandoned  by  the  animals  that  built  them.  The 
ponds  and  swamps  due  to  the  work  of  beavers  number  tens  of  thousands, 
and  have  produced  important  changes  in  the  minor  features  of  the  surface 
of  the  continent.  Many  of  these  ponds,  after  becoming  choked  with 
vegetation  and  converted  into  peat  swamps,  have  been  drained  and 
furnish  rich  garden-lands. 

Where  brooks  and  creeks  flow  through  forested  regions,  it  fre- 
quently happens  that  large  trees  fall  across  them  and  retain  the  sticks 
and  leaves  swept  along  by  the  current.  When  such  a  start  is  made,  the 
mud  carried,  especially  during  freshets,  is  lodged  among  tlie  leaves  and 
branches,  and  tends  still  farther  to  obstruct  the  drainage  and  lead  to  the 
formation  of  swamps  and  lakes.  This  process  has  been  observed  espe- 
cially in  Red  river,  Louisiana,  where  timber  rafts  several  square  miles  in 
area,  and  covered  with  living  vegetation,  form  floating  islands  and  dam 
the  streams  so  as  to  cause  their  waters  to  spread  out  in  shallow  lakes 
twenty  to  thirty  miles  in  length.^ 

Numerous  instances  in  the  Yukon  river,  in  Alaska,  were  observed  by 
the  writer,  where  lateral  branches  of  the  stream  and  the  passage  wa3's 
between  islands,  were  closed  by  accumulations  of  drift  logs  that  greatly 
obstructed  the  flow  of  the  waters.  In  some  instances  these  accumulations, 
called  "  wood  yards  "  by  steamboat  men,  are  several  acres  in  extent. 

Still  another  way  in  which  organic  agencies  lead  to  the  formation  of 
basins  may  be  observed  in  swamps  where  vegetable  matter  buried  beneath 
mud  and  clay  is  undergoing  decomposition.  Openings  similar  to  those 
produced  in  alluvial  deposits  by  the  violent  escape  of  water  during  earth- 
quakes, but  not  necessarily  connected  with  such  disturbances,  are  formed 
in  marshes  by  the  violent  escape  of  gases  from  below.  Instances  of  this 
occurrence  have  come  under  the  writer's  notice  on  Smoke  Creek  desert, 

1  Charles  Lyell.  "  Principles  of  Geology."  llth  ed.,  Vol.  1,  p.  441.  Humphreys  &  Abbott. 
"Report  on  the  Physics  and  Hydraulics  of  the  Mississippi,"  Professional  Papers,  Corps  of 
Engineers,  U.  S.  A.,  1861,  p.  37. 


28  LAKES    OF    NOETH    AMERICA. 

Xevada,  and  on  swampy  areas  near  Sandusky,  Ohio.  When  these  gas 
erui)tions  occur,  the  soft  mud  is  sometimes  thrown  to  a  distance  of  one  or 
two  hundred  feet,  and  conical  depressions  are  formed  which  in  some  of  the 
instances  observed,  are  twenty  feet  or  more  in  depth.  The  caving  in  of 
the  banks'  holes  sometimes  leads  to  the  formation  of  pools  fifty  or  sixty 
feet  in  diameter.  The  circular  ponds  frequently  to  be  seen  in  swampy 
regions,  when  not  due  to  encroaching  vegetation,  probably,  in  many 
instances,  originated  in  the  manner  here  noted. 

The  generation  of  gases,  principally  carbureted  hydrogen,  in  the  soft 
mud  of  the  ^Mississippi  delta,  causes  elevations  known  as  "  mud  lumps," 
which  in  some  instances  are  twenty-five  feet  high.  Inequalities  pro- 
duced in  this  manner  might  easily  lead  to  the  obstruction  of  di-ainage 
and  the  formation  of  lakes,  but  no  instance  of  such  an  occurrence  seems 
to  have  been  reported. 

It  has  frequently  Ijeen  observed  that  cattle  on  visiting  swampy  places 
carry  away  considerable  quantities  of  mud,  adhering  to  their  feet  and 
matted  in  their  hair.  In  arid  countries  where  drinking  places  are  usually 
small  and  widely  scattered,  they  are  visited  by  cattle  and  other  animals  in 
large  numbers  and  a  marked  enlargement  of  the  Avater  holes  is  jDroduced 
in  the  manner  just  stated.  This  process  was  more  important  when 
the  plains  of  North  America  were  densel}-  inhabited  by  bisons.  ]\Iany 
perennial  pools  and  still  more  numerous  depressions  that  are  water-tilled 
only  during  rainy  seasons,  ai-e  known  as  "buffalo-wallows,"  and  are 
believed  to  owe  their  origin  to  a  great  extent  to  the  carrying  away  of 
mud  entangled  in  the  thick  hair  of  the  animals  after  which  they  are 
named. 

In  the  Appalachians  there  are  several  water  holes,  usually  on  the 
crests  of  ridges,  that  are  called  "bear-wallows,"  and  are  said  to  have 
been  formed  by  bears  that  sought  moist  })laces  in  which  to  cool  them- 
selves during  hot  weather.  As  is  well  known,  swine  have  a  similar 
habit. 

Basins  due  to  inovenients  In  the  earth's  crust.  —  Great  changes  in 
the  earth's  crust  have  produced  continents  and  ocean-basins,  Avhile  smaller 
movements  on  land  areas  have  resulted  in  the  formation  of  mountains  and 
valleys.  During  the  growth  of  mountains  it  sometimes  happens  tliat  the 
region  between  different  systems  or  between  two  or  more  ranges,  becomes 
enclosed  so  as  to  form  a  basin.  This  process  has  been  in  action  in  various 
localities  since  land  first  appeared,  and  during  the  course  of  geological  eras 


ORIGIN    OF    LAKE    BASINS.  29 

must  have  resulted  in  the  formation  of  many  lakes  ;  but  examples  of  water 
bodies  of  this  type  are  rare  at  the  present  time,  principally  for  the  reason 
that  the  deformation  of  the  earth's  crust  usually  goes  on  slowly  and  the 
depressions  lormed  are  drained  or  filled  with  sediments  as  rapidly  as 
they  are  formed. 

The  best  examples  on  this  continent  of  basins  formed  by  the  upheaval 
of  mountains  around  them,  occur  in  the  great  area  of  interior  drainage 
between  the  Rocky  mountains  and  the  Sierra  Nevada.  The  majority  of 
the  minor  basins  in  this  region,  however,  are  due  to  secondary  causes, 
but  the  vast  seas,  such  as  lakes  Bonneville  and  Lahontan,  which  for- 
merly existed  there,  occupied  l)asins  of  the  character  here  referred  to. 

The  Laurentian  lakes  are  held  in  basins  produced  in  part  by  crustal 
movements  affecting  large  areas,  and  in  part  by  conditions  resulting  from 
other  causes.  Basins  are  also  produced  by  less  extensive  elevations  and 
depressions  of  the  earth's  crust.  The  corrugation  of  a  region,  owing  to 
the  formation  of  a  series  of  approximately  parallel  folds,  known  as  anti- 
clinals  and  synclinals,  as  in  the  case  of  the  Appalachian  mountains,  nuist 
frequently  produce  basins  in  which  water  would  be  retained,  were  the 
process  allowed  to  go  on  without  some  counteracting  agency  ;  but  here 
again,  the  movements  are  usually  so  slow  that,  especially  in  humid  regions, 
the  depressions  produced  are  destroyed  as  rapidly  as  they  are  formed. 
AVhile  lakes  in  synclinal  basins  might  be  expected  to  be  of  common  occur- 
rence, they  are  in  reality  so  rare  that,  so  far  as  I  am  aware,  none  of  the 
tens  of  thousands  of  the  lakes  of  America  can  be  pointed  to  as  examples. 

There  is  still  another  variety  of  earth  movements  in  many  instances 
less  gradual  than  those  referred  to  above,  to  which  many  lakes  owe  their 
origin. 

Fractures  in  the  earth's  crust  occur  in  disturbed  regions  and  may  be 
scores  or  even  hundreds  of  miles  in  leng-th.  Tlie  edges  of  the  broken 
strata  on  one  side  of  a  fracture  are  sometimes  elevated,  or  those  on  the 
opposite  side  depressed,  thus  forming  what  is  known  as  a  "  fault."'  The 
growth  of  faults  sometimes  goes  on  so  slowly  that  no  pronounced  changes 
in  topography  result,  for  the  reason  that  the  rocks  on  the  u^jheaved  side 
of  the  fracture  are  eroded  away  as  fast  as  tlie}'  are  laised.  At  other 
times,  however,  mountain  ranges  are  produced,  in  which  the  strata  are 
inclined  aAvay  from  the  steep,  broken  face  overlooking  the  line  of  fracture. 
In  regions  where  such  mountain  ranges  have  been  formed  with  comparative 
rapidity  and  where  denuding  agencies  are  weak,  great  disturbances  in  the 
drainage  result,  and  "  fault  basins  "  are  common.     Numerous  basins  of 


30  LAKES    OF    NORTH    AMERICA. 

this  character  occur  in  the  Arid  region  and  especially  in  Nevada  and 
southeastern  California,  but  probably  the  most  typical  example  is  the 
one  occu^^ied  by  Abert  lake,  Oregon. 

Alonof  the  east  side  of  Abert  lake  there  is  a  long  line  of  mag-nificent 
palisades,  several  hundred  feet  high,  formed  by  the  precipitous  face  of  an 
eastward  dipping  fault  block  ;  the  lake  washes  the  base  of  this  escape- 
ment and  occupies  the  depression  formed  by  the  suljsidence  of  the  rocks 
on  the  west  side  of  the  fracture.  Something  of  the  appearance  of  Abert 
lake,  as  seen  from  the  crest  of  the  jDalisades  a  few  miles  to  south  of  its 
southern  end,  and  also  of  the  general  structure  of  the  underlying  rocks, 
may  be  gathered  from  the  accompanying  illustration.  The  lake  is  about 
fifteen  miles  long  with  an  average  width  of  nearly  four  miles,  and  is 
shallow.  It  receives  the  water  of  a  single  creek,  but  does  not  overflow 
and  is  intensely  alkaline. 

Many  of  the  lakes  of  the  Arid  region  are  of  the  Abert  tj'pe,  but 
usually  the  great  depressions  in  which  they  occur  have  become  deeply 
filled  with  the  sediments  of  older  water  bodies,  and  they  may  be  considered 
as  occupying  depressions  on  new  land  areas,  or  as  belonging  to  the  class 
of  basins  here  considered,  as  one  prefers. 

In  some  instances  the  faulting  that  gave  origin  to  the  characteristic 
topography  of  the  Great  Basin  region  has  been  continued  to  the  present 
time,  and  produced  escarpments  across  the  bottoms  of  the  deeply  filled 
valleys,  so  that  the  existing  water-bodies  are  confined  in  part  by  recent 
fault  scarps.  An  instance  of  this  nature  is  furnished  by  Mono  lake,  Cali- 
fornia, which  washes  the  base  of  a  precipice  formed  by  a  recent  movement 
of  the  great  Sierra  Nevada  fault.  A  similar  association  has  also  been 
observed  in  connection  with  several  of  the  lakes  of  western  Nevada. 

When  a  fault  crosses  the  course  of  a  river,  the  edge  of  the  upturned 
block  may  rise  so  slowly  that  the  stream  is  able  to  maintain  its  course 
and  cut  a  channel  through  the  obstruction  as  it  is  elevated,  and  a  lake  is 
not  formed.  Numerous  instances  of  this  nature  have  been  observed  by 
the  writer  in  the  central  part  of  the  state  of  Washington,  where  the 
Columbia  and  the  Yackima  river  have  eroded  deep  narrow  gorges  through 
the  edges  of  fault  blocks  that  were  upheaved  across  their  courses. 

With  basins  produced  by  faulting,  as  in  other  instances  of  surface 
inequalities  due  to  movements  of  the  earth's  crust,  the  question  whether  a 
lake  will  l)e  formed  or  not,  is  answered  mainly  by  the  climatic  conditions. 
In  arid  regions  the  surface  effects  of  orographic  movements  are  counter- 
acted by  erosion  but  slowly;  while  in  countries  with  abundant  drainage 


ORIGIN    OF    LAKE    BASINS.  31 

degradation  goes  on  energetically,  and  unless  the  deformation  of  the 
surface  is  comi^aratively  rapid,  no  pronounced  topographic  changes  result. 
It  is  the  ratio  between  the  rate  of  deformation  and  denudation  which  de- 
termines whether  l)asins  shall  be  formed  or  not.  J-Lvidently  tlie  most  favor- 
able regions  for  studying  the  effects  of  movements  in  the  earth's  crust  on 
the  surface  relief,  are  those  in  which  the  meteoric  and  aqueous  agencies 
are  least  energetic,  namely,  in  arid  regions. 

Basins  due  to  land-slidos.  —  On  steep  slopes  great  masses  of  rocks 
and  earth  not  infrequently  break  away,  especially  after  heavy  rains,  and 
descend  suddenly  as  land-slides  into  the  adjacent  valley.  AVhen  this 
occurs,  tlie  drainage  in  the  valley  may  be  obstructed  so  as  to  cause  lakes 
to  form.  Avalanches  of  snow  and  loose  rocks  also  produce  similar  results, 
but  of  a  less  pronounced  character. 

Small  lakes  originate  in  many  cases  on  the  surface  of  land-slides 
owing  to  the  fact  that  such  surfaces,  after  the  descending  mass  has  come 
to  rest,  usually  incline  toward  the  cliffs  from  whu-h  they  l)roke  away,  in 
such  a  manner  as  to  enclose  basins.  At  times,  a  land-slide  plows  u})  the 
floor  of  the  valley  into  which  it  plunges  and  forms  a  ridge,  not  uidike  a 
terminal  moraine,  which  may  also  act  as  a  dam  and  hold  a  lake  in  check. 
Examples  of  basins  formed  in  each  of  these  several  ways  have  been 
examined  by  the  writer  in  the  state  of  Washington  i  and  in  other  regions, 
but  need  not  be  described  at  this  time. 

Basins  due  to  chemical  action.  —  In  limestone  countries  the  drainage 
is  often  subterranean  and  finds  its  way  tlirough  caverns  formed  by  the 
solution  of  the  rock.  The  roofs  of  such  caverns  fall  in  as  the  general 
erosion  of  the  region  progresses,  and  obstruct  the  drainage  cliaimels  so  as 
to  form  lakes.  The  surface  waters  reach  underground  channels  througli 
openings  teinied  "sink-holes,"  or  "swallow-holes,"  wliieh  are  eidarged  by 
solution,  and  fre(iuently  become  closed  so  as  to  hold  ponds.  In  portions 
of  Kentucky  and  throughout  the  Great  Appalachian  valley,  where  the 
underlying  rock  is  limestone,  circular  ponds  of  this  naluic  are  so  numer- 
ous that  they  give  cliaracter  to  the  landscape.  Lakes  also  occur  in  tlie 
caverns  themselves,  owing  to  various  causes,  the  most  frequent  being  the 
falling  of  portions  of  their  stalactic  roofs,  as  may  be  seen  in  Mammoth 
and  Luray  caverns. 

1  "Geological  Keconnoissance  in  Central  Washington,"  U.  S.  Geol.  Surv.,  Bulletin  No.  108. 


32  LAKES    OF    NORTH    AMERICA. 

Basins  of  small  size,  due  to  chemical  precipitation,  occur  in  connection 
with  springs  that  deposit  calcareous  tufa  or  siliceous  cinter.  Many  ex- 
amples of  pools  formed  in  this  way  occur  in  the  Yellowstone  National 
Park  and  in  other  hot  spring  regions  of  the  Cordilleras.  Near  the  west 
shore  of  ^lono  lake,  California,  there  is  a  castle-like  bowl  of  calcareous 
tufa,  fully  50  feet  liigh  and  from  150  to  200  feet  in  diameter,  with  several 
long  aqueduct-like  branches,  which  was  formed  from  the  water  of  a  spring 
that  has  now  ceased  to  flow.  Far  out  on  the  desert  valleys  of  Utah  and 
Nevada  one  sometimes  finds  circular  basins  with  rims  of  tufa  from  a  few 
inches  to  three  or  four  feet  high,  and  holchng  beautifully  clear  water  with 
a  temperature  approaching  the  boiling  point.  In  other  instances,  these 
deposits  rise  several  feet  above  the  adjacent  surface  and  resemble  volcanic 
craters.     In  their  summits  there  are  frequently  steaming  caldrons. 

In  regions  underlain  by  gypsum,  rock  salt,  and  other  easily  soluble 
substances,  depressions  are  formed  on  account  of  the  removal  in  solution 
of  the  rocks  beneath  and  the  s'^sidence  of  the  surface. 

Gypsum  is  thought  by  some  geologists  to  owe  its  formation  to  the 
alteration  of  limestone  by  the  passage  through  it  of  sulphurous  gases  or 
of  sulphurous  waters.  When  this  occurs,  the  volume  of  the  deposit  is 
increased  and  the  ground  above  may  be  elevated  into  mounds,  and  thus 
obstruct  the  drainage. 

CONCLUSION. 

In  this  chapter  an  attempt  has  been  made  to  describe  briefly  the 
principal  types  of  lake  basins  occurring  in  North  America,  to  indicate  the 
processes  by  which  they  have  been  formed,  and  to  show  to  some  extent, 
where  they  severally  belong  in  the  history  of  topographical  development. 

Many  basins  have  resulted  from  the  action  of  more  than  one  agency, 
and  in  not  a  few  instances  several  agencies  have  cooperated  in  their 
l^roduction.  Basins  of  a  composite  character  have  thus  originated,  but 
the  principal  cause  leading  to  their  existence  is  usually  so  pronounced 
that  when  carefully  studied,  they  may  without  great  violence  be  referred 
to  some  one  of  the  types  here  described. 

The  study  of  lakes  has  shown  that  they  frequently  have  a  long  and 
varied  history,  which  is  no  less  interesting  and  instructive  than  the  story 
of  the  origin  and  decadence  of  the  hills  that  are  reflected  in  their  glassy 
depths.  Some  of  the  phases  of  their  not  uneventful  lives  are  described 
in  the  succeeding  chapters. 


CHAPTER   II. 

MOVEMENTS     OP     LAKE    ABATERS    AND    THE    GEOLOGICAL 
FUNCTIONS   OF    LAKES. 

Tides.  —  The  waters  of  lakes  are  influenced  by  the  attraction  of  the 
sun  and  moon  in  the  same  manner  as  the  waters  of  the  ocean.  Owing 
to  the  comparatively  small  extent  of  inland  water-l)odies,  however,  the 
rise  of  their  waters  is  so  small  that  it  is  not  noticeable,  and  can  only  be 
determined  by  refined  measurements. 

Observations  made  by  the  U.  S.  Lake  Survey  at  Chicago,  have  shown 
that  Lake  Michigan  has  a  tide  with  an  amplitude  of  1^  inches  for  the 
neap  tide  and  3  inches  for  the  spring  tide. 

Waves  and  currents.  —  The  waters  of  fresh  lakes  respond  to  the 
influences  of  the  wind  more  quickly  than  the  heavier  waters  of  the  ocean, 
but;  the  waves  produced  are  smaller  and  less  regular  than  in  the  open  sea. 
On  the  Laurentian  lakes,  waves  from  15  to  18  feet  in  amplitude  have 
been  observed  during  long  continued  storms.  The  heavy  ground  swell 
of  the  ocean  is  but  faintly  reproduced  by  the  fresh  Avater  "seas."  During 
rousfh  weather  on  the  lakes  the  waves  are  more  like  the  short,  "chop 
seas  "  than  the  heavy  surges  of  the  open  ocean. 

The  friction  of  the  wind  on  the  surfaces  of  lakes  produces  very  decided 
movements  in  their  waters.  In  their  central  portions,  especially,  there  are 
frequently  strong  currents  due  to  this  cause,  in  addition  to  the  slow 
movement  of  the  waters  toward  an  outlet.  A  study  of  the  currents  of 
the  Laurentian  lakes  has  been  undertaken  by  the  United  States  Weather 
Bureau,  by  means  of  bottles  containing  a  record  of  the  locality  where 
they  were  set  adrift  and  a  request  that  the  finder  will  note  the  locality 
where  they  are  recovered  and  transmit  the  record  to  the  Chief  of  the 
Weather  Bureau.  The  results  of  observations  made  in  the  summer  season 
of  18.02  and  1893,  have  been  published,^  and  the  general  courses  of  the 
currents  so  far  as  ascertained,  indicated  on  a  chai-t  which  is  reproduced 
on  Plate  7.  The  effects  of  the  prevailing  westerly  winds  on  the  surface 
movement  of  certain  of  the   Laurentian  lakes,  is  indicated  by  the  trend 

1  U.  S.  Department  of  Agriculture,  Weather  Bureau,  Bulletin  B. 


34  LAKES    OF    NORTH    AMERICA. 

of  the  principal  currents.  When  the  hirger  axis  of  a  hike  coincides  with 
the  direction  of  the  prevailing  winds,  a  surface  current  is  established 
through  its  center,  as  in  the  case  of  lakes  Erie  and  Ontario,  with  return 
currents  and  eddies  along  the  shore  and  about  islands.  When  lakes  lie 
athwart  the  prevailing  winds  the  main  currents  combine  with  the  return 
currents  and  form  minor  swirls,  as  is  shown  on  the  chart  in  the  case 
of  lakes  Michigan  and  Huron.  In  Lake  Superior  there  is  a  general 
circulation  which  follows  the  main  shore  lines,  but  its  course  has  not  been 
fully  determined.  It  has  been  found  that  the  currents  of  the  Laurentian 
lakes  have  in  general  a  speed  of  from  4  to  12  miles  a  day,  but  in  certain 
observed  instances,  this  is  increased  to  21-  to  4  miles  an  hour  or  from  36 
to  96  miles  a  day. 

The  cuiTcnts  in  the  central  part  of  a  lake  produce  slight  if  any 
changes  on  the  topography  of  its  basin,  but  when  they  follow  the  shore 
important  results  may  follow.  When  the  wind  blows  obliquely  to  the 
shore,  strong  currents  are  frequently  produced  which  follow  the  general 
trend  of  the  coast,  but  cut  across  bays  and  inlets.  These  currents,  with 
the  assistance  of  waves,  sweep  along  sand  and  gravel,  and  produce  impor- 
tant changes  on  the  bottom,  particularly  when  the  water  is  shallow.  The 
rQle  played  by  waves  and  currents  in  modifying  topography  is  considered 
with  some  detail  in  the  next  succeeding  chapter. 

Strong  winds  blowing  in  a  nearly  uniform  direction  for  several  days 
cause  the  waters  of  lakes  to  move  with  them,  and  to  rise  on  the  shores 
against  which  they  are  driven,  so  as  frequently  to  produce  disastrous 
inundations.  A  gale  blowing  from  the  north  over  Lake  Michigan  has 
been  observed  to  cause  a  rise  of  seven  feet  at  Chicago.  In  Novem- 
ber, 1892,  a  storm  from  the  west  caused  the  waters  of  Lake  Erie 
near  Toledo,  to  fall  between  eight  and  nine  feet  below  the  normal  fair 
weather  level.  At  the  same  time,  unusually  high  water  was  experienced 
at  the  east  end  of  the  lake.  The  differences  in  the  level  of  the  waters  of 
Lake  Erie,  at  Buffalo,  between  a  high-water  stage  produced  by  an  east- 
ward blowing  gale,  and  a  low- water  stage  accompanying  a  westward  or 
off-sliore  gale,  has  been  observed  to  amount  to  151-  feet.  An  eastward 
movement  of  the  waters  of  Lake  Superior  has  been  known  to  accom- 
pany a  gale  from  the  west  and  to  produce  an  unusual  rise  in  the  water 
of  St.  Mary's  river. 

The  height  to  which  the  waters  reach  on  lake  shores,  owing  to  strong 
winds,  establishes  the  upper  limit  of  wave-action,  and  leads  to  the  forma- 
tion of  storm  beaches  at  an  elevation  of  several  feet  above  the  normal 


MOVEMENTS    OF    LAKE    WATERS.  35 

stacre.  When  the  shores  of  a  hike  are  low,  broad  areas  are  inundated 
during  storms  that  sweep  the  waters  towards  them.  New  outlets  may 
be  established  at  such  times  across  low  divides,  and  lead  to  important 
changes  in  drainage. 

Seiclie.  —  Lake  waters  are  also  sensitive  to  changes  in  atmospheric 
pressure.  In  some  instances  variations  of  level  during  calm  weather, 
amounting  to  several  feet,  have  been  observed,  and  are  supposed  to  be  due 
to  sudden  changes  in  barometric  pressure  on  different  portions  of  the 
water  surface.  Besides  these  larger  movements,  which  can  be  correlated 
with  atmospheric  changes,  and  are  known  as  seiches,^  there  are  certain 
rhythmical  pulsations  producing  a  difference  of  level  of  as  much  as  four 
or  five  inches  during  calms,  when  no  variation  in  atmospheric  i)ressure  of 
an  analogous  character  can  be  detected.  These  minor  movements  are 
not  thoroughly  understood. 

These  and  other  changes  of  a  similar  nature  are  of  great  interest  in 
connection  with  meteorological  studies,  but  have  little  if  any  geological 
significance. 

It  is  to  be  expected  that  earthquakes  Avould  produce  "  tidal  waves  "  in 
lakes  similar  to  those  occurring  in  the  ocean,  but  observations  in  this 
connection  are  wanting. 

Teniperature.  —  Lake  waters  are  warmed  by  tlie  sun's  rays  and  by 
contact  with  the  air.  It  has  also  been  thought  by  some  that  very  deep 
lakes  may  have  their  bottom  temperatures  modified  Ijy  the  general  iiitei'iial 
heat  of  the  earth,  but  observations  do  not  seem  to  support  this  conclu- 
sion. Water  is  a  poor  radiator  and  an  indifferent  conductor  of  heat,  and 
does  not  respond  to  atmospheric  changes  of  temperature  as  quickly  as  do 
rock  surfaces.  Shallow  lakes  are  v^armed  throughout  by  the  summer's 
heat  and  chilled  to  the  Ijottom  l)y  the  winter's  cold  ;  but  their  temi)era- 
ture  is  much  more  uniform  than  that  of  the  adjacent  air.  The  shal- 
low lakes  of  the  Northern  states  have  been  found  to  have  a  nearly 
uniform  temperature  during  the  summer  months  of  75°  Fahrenlieit.  In 
winter  their  temperature  in  general  is,  of  course,  32°  Fahrenheit.  In 
lakes  having  a  depth  in  excess  of  about  800  feet,  more  interesting  condi- 
tions are  found.  The  temperatures  of  deep  lakes  are  ascertained  by  means 
of   self-registering    thermometers    atjtached    to    sounding  lines.      In   tliis 

IE.  A.  Perkins.  "The  Seiclie  in  American  Lakes,"  American  Meteorological  Jmir., 
Oct.,  1893. 


36 


LAKES    OF    NORTH   AMERICA. 


way  accurate  measurements  of  temperature  at  various  depths  have  been 
made  in  a  number  of  hikes,  both  in  America  and  in  Europe,  with  remark- 
ably consistent  results.  Of  the  observations  thus  far  made  in  this  country, 
the  most  instructive  are  by  Professor  John  Le  Conte,i  in  Lake  Tahoe, 
California.     From  the  report  of  these  observations  I  quote  the  following  : 

"These  experiments  were  executed  between  the  11th  and  18th  of  August,  1873. 
The  same  general  results  were  obtained  in  all  parts  of  the  lake.  The  following  table 
contains  an  abstract  of  the  average  results,  after  correcting  the  thermometric  indications 
by  comparison  with  a  standard  thermometer : 


Obs. 

Depth  ix  Feet. 

Depth  in  Meters. 

Temperature. 

Fahrenheit  Scale. 

Centigi-ade  Scale. 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

0  =  Surface. 
50 
100 
150 
200 
250 
300 

330  (Bottom) 
400 

480  (Bottom) 
500 
600 

772  (Bottom) 
1506  (Bottom) 

0  =  Sui'face. 

15.24 

30.48 

45.72 

60.06 

76.20 

91.44 
100.58 
121.92 
146.30 
152.40 
182.88 
235.30 
459.02 

67° 

63° 

55° 

50° 

48° 

47° 

46° 

45..5° 

45° 

44.5° 

44° 

43° 

41° 

39.2° 

19.44° 
17.22° 
12.78° 
10° 
8.89° 
8.38° 
7.78° 
7.50° 
7.72° 
6.94° 
6.67° 
6.11° 
5° 
4° 

"It  will  be  seen  from  the  foregoing  numbers  that  the  temperature  of  the  water 
decreases  with  increasing  depth  to  about  700  or  800  feet  (213  or  244  meters),  and 
below  this  depth  it  remains  sensibly  the  same  down  to  1,506  feet  (459  meters).  This 
constant  temperature  which  prevails  at  all  depths  below  say  250  meters  is  about 
4°  C.  (39.2°  Falu-.).  This  is  precisely  what  might  have  been  expected;  for  it  is  a 
well-established  physical  property  of  fresh  water,  that  it  attains  its  maximum  density  at 
the  above-indicated  temperature.  In  other  words,  a  mass  of  fresh  water  at  the  tempera- 
ture of  4°  C.  has  a  gi-eater  weight  under  a  given  volume  (that  is,  a  cubic  inch  unit 
of  it  is  heavier  at  this  temperature)  than  it  is  at  any  temperature  either  higher  or 
lower.  Hence,  when  the  ice-cold  water  of  the  snow-fed  streams  of  spring  and  summer 
reaches  the  lake,  it  naturally  tends  to  sink  as  soon  as  its  temperature  rises  to  4°  C. ; 
and,  conversely,  when  winter  sets  in,  as  soon  as  the  summer-heated  surface-water  is 

1"  Physical  Studies  of  Lake  Tahoe,"  Overland  Monthly,  2d  Series,  vol.  2,  1883,  pp. 
606-516,  595-612 ;  vol.  3,  1894,  pp.  41-46. 


MOVEMENTS  OF  LAKE  WATERS.  37 

cooled  to  4°,  it  tends  to  sink.  Any  further  rise  of  the  temperature  of  the  surface-water 
during  the  warm  season,  or  fall  of  temperature  during  the  cold  season,  alike  produces 
expansion,  and  thus  causes  it  to  float  on  the  heavier  water  below;  so  that  water  at 
4°  C.  perpetually  remains  at  the  bottom,  while  the  varying  temperature  of  the  seasons 
and  the  penetration  of  the  solar  heat  only  influence  a  surface  stratum  of  about  250 
meters  in  thickness.  It  is  evident  that  the  continual  outflow  of  water  from  its  shallow 
outlet  cannot  disturb  the  mass  of  liquid  occupying  the  deeper  portions  of  the  lake.  It 
thus  results  that  the  temperature  of  the  surface-stratum  of  such  bodies  of  fresh  water 
for  a  certain  depth  fluctuates  with  the  climate  and  with  the  seasons  ;  but  at  the  bottom 
of  deep  lakes  it  undergoes  little  or  no  change  throughout  the  year,  and  ajiproaches  to 
that  which  corresponds  to  the  maximum  density  of  fresh  water." 

Influence  of  lakes  on  climate.  —  Inland  water  bodies  exert  an  impor- 
tant influence  on  the  climate  of  their  shores,  in  reference  especially  to 
temperature  and  humidity,  and  also  on  the  direction  and  character  of  the 
more  gentle  winds.  The  surface  waters  of  lakes  receive  their  temperature 
in  a  great  measure  from  the  air  in  contact  with  them,  and  are  warmed  or 
cooled  at  rates  having  some  relation  to  their  depth.  The  temperature  of 
shallow  lakes  varies  but  little  from  that  of  the  adjacent  atmosphere,  but 
changes  less  rapidly  for  the  reason,  already  stated,  that  water  surfaces  are 
poor  radiators.  The  differences  between  the  rates  of  radiation  between 
adjacent  land  and  water  surfaces,  affect  the  temperature  of  the  air  above 
them,  and  in  calm  weather  give  origin  to  lake  and  land  breezes. 

The  tens  of  thousands  of  small  lakes  scattered  over  the  glaciated 
portions  of  North  America  have  an  important  combined  influence  on  the 
general  climate,  although  their  effects  may,  perhaps,  be  diflicult  of  direct 
determination.  These  lakes  cool  and  moisten  the  atmosphere  by  evapora- 
tion during  the  hot  summer  montlis,  and  when  they  freeze  as  winter 
approaches,  a  vast  amount  of  "  latent  heat "  is  liberated  and  moderates 
the  fall  in  temperature.  It  is  stated  by  physicists  that  every  ton  of  water 
converted  into  ice  gives  out  as  much  heat  as  Avould  be  required  to  raise 
the  same  quantity  of  water  from  30°  to  174°  Fahrenheit.  A  reverse 
process,  not  so  congenial  to  the  welfare  of  man,  takes  place,  however, 
when  the  ice  melts  in  spring,  as  then  an  amount  of  energy  equal  to  that 
previously  lost,  must  be  again  absorbed  in  order  that  the  ice  may  change 
to  water.  The  warm  southern  winds  are  thus  chilled  and  the  opening  of 
the  flowers  delayed. 

Deep  lakes,  as  already  seen,  have  a  uniform  bottom  temperature  of  30 
degrees  of  the  Fahrenheit  scale,  and  do  not  freeze  in  winter  except  about 
their  shores  where  the  water  is  shallow,  for  the  reason  that  the  low 
temperature  of  the  air  aljove  them  does  not  continue  long  enough  for  the 


38  LAKES    OF    NORTH    AMERICA. 

entire  water-boc^y  to  become  cooled  to  the  degree  of  maximum  density. 
Until  this  happens  the  water  cooled  at  the  surface  from  contact  with  the 
air,  has  its  density  increased  and  sinks,  and  is  replaced  by  warmer  and 
consequently  lighter  watei-,  rising  from  below,  and  ice  cannot  foi-m. 

The  surface  waters  of  deep  lakes  are  thus  above  the  mean  temperature 
of  the  adjacent  atmos})here  in  winter ;  Ijut  in  summer  they  are  cooler  than 
the  air,  as  the  warmed  surface  layer  loses  heat  by  conduction  downward. 
The  winds  that  blow  over  them  are  thus  tempered  in  a  manner  congenial 
to  the  growth  of  vegetation  both  in  warm  and  in  cold  weather. 

The  influence  of  the  Laurentian  lakes  on  the  climate  of  their  shores 
is  well  marked,  as  was  clearly  shown  many  years  since  by  Alexander 
Winchell.^  On  charts  that  have  appeared  showing  the  winter  and  sum- 
mer isobar,  that  is,  lines  drawn  through  the  various  localities  having  the 
same  mean  temperature,  the  lines  showing  the  mean  sunnner  temperature 
curve  northward  in  the  vicinity  of  Lake  Michigan  especially,  while  the 
lines  indicating  mean  winter  temperature  present  an  equally  marked 
southern  curvature,  showing  that  the  lakes  cool  the,  air  that  passes  over 
them  in  summer  and  warm  it  in  winter.  The  genial  influence  of  the 
lakes  is  also  plainly  to  be  seen  in  the  distribution  of  the  fruit-l)elts  of 
Michigan,  Ohio,  and  New  York. 

If  we  should  construct  a  map  showing  the  mean  humidity  of  the  air, 
by  drawing  lines  through  the  localities  having  the  same  "relative  humid- 
ity," the  influence  of  the  lakes  would  be  quite  as  apparent  as  in  the  case 
of  the  isothermal  lines,  but  the  curvature  in  both  winter  and  summer 
would  be  southward. 

The  amelioration  of  climate  produced  by  large  inland  water-l)odies 
has  an  important  influence  on  the  flora  and  fauna  of  their  borders,  and 
therefore  on  the  character  of  the  fossils  entombed  in  their  sediments. 
Another  fact  of  geological  interest  in  this  connection,  is  that  rocks  decay 
more  rapidly  under  warm,  moist  climates  than  in  arid  or  in  Arctic  regions, 
and  deeper  and  richer  soils  are  produced.  This,  again,  influences  the 
life  of  lake  regions,  and  is,  perhaps,  of  sufficient  importance  to  be  con- 
sidered in  interpreting  the  records  of  ancient  inland  water-bodies. 

Influence  of  lakes  on  the  flow  of  streams.  —  Lakes  act  as  storage 
reservoirs  and  regulate  the  fioAV  of  the  streams,  of  which  they  are  enlarge- 
ments.    In  the  case  of  a  river  subject  to  sudden  freshets,  the  disastrous 

1 '■  The  isothermals  of  the  Lake  Region,"  Am.  Assoc.  Adv.  Sci.,  Proc,  vol.  10,  Troy 
Meeting,  1870,  pp.  100-117. 


MOVEMENTS    OF    LAKE    WATERS.  39 

effects  of  a  sudden  rtee  would  l^e  checked,  and  even  entirely  averted,  if 
a  lake  of  sufficient  size  existed  in  its  middle  course,  or  if  there  Avere  a 
numher  of  lakes  on  its  tributary  streams. 

The  modulating  influence  of  lakes  on  the  flow  of  streams  is  Avell 
known  to  hydraulic  engineers ;  and  it  has  l)een  proposed  to  regulate  the 
flow  of  the  jNIississippi  by  Ijuilding  storage  reservoirs  on  its  head  waters. 
Such  reservoirs  could  be  filled  during  floods  and  the  Avater  allowed  to 
escape  when  the  danger  stage  had  passed.  In  this  manner  the  disasters 
resulting  from  annual  freshets  could  be  averted  and  navigation  improved 
during  the  seasons  of  low  water. 

The  effect  of  gales  in  heaping  up  the  waters  of  lakes  on  the  shores 
against  which  they  blow  has  already  been  noted,  and  an  instance  cited 
where  the  waters  of  St.  jNIary's  river  were  suddenly  raised  by  a  gale  on 
Lake  Superior.  A  rise  of  the  water  in  streams  flowing  from  large  lakes, 
due  to  this  cause,  is  exceptional,  however,  and  by  no  means  as  destructive 
as  the  fluctuations  produced  by  storms  and  melting  snow  on  water  courses 
that  are  without  the  regulating  influences  of  large  lakes. 

The  sudden  escape  of  lakes  held  l)y  dams  of  ice  also  causes  floods  in 
the  streams  below,  as  in  the  case  already  cited  of  the  Rhone,  when  ]\Iar- 
jelen  lake  is  drained,  and  of  the  Stickeen,  where  the  glacial-held  lakes  on 
its  tributaries  break  their  icy  bands. 

The  rise  of  Lake  Bonneville  until  it  found  an  outlet  and  then  ra})idly 
cut  down  its  channel  of  discharge  through  unconsolidated  material,  as 
Avill  be  described  in  advance,  is  supposed  to  have  caused  a  great  rise  in 
Snake  river,  to  which  it  became  tributary,  hi  these  and  other  ways  that 
might  be  cited,  it  appears  that  lakes  may  cause  floods  in  their  draining 
streams  as  well  as  avert  them. 

Lakes  as  settling-  basins.  —  The  streams  flowing  into  lakes  are  fre- 
quently tu)'bid  and  heavy  with  sediment,  especially  after  storms,  but  the 
rivers  flowing  from  them  are  usually  clear  and  free  from  all  l)ut  possibly 
the  finest  of  matei'ial  in  suspension.  During  the  slow  })assage  of  the 
waters  through  a  lake  which  has  an  outlet,  the  material  in  suspension 
falls  to  the  bottom  and  contributes  to  the  filling  of  the  basin,  Avliile  the 
clarified  waters  flow  on. 

The  fact  that  l)odies  of  standing  water  retain  the  mineral  matter 
brought  to  them  in  suspension,  is  illustrated  more  or  less  perfectly  in 
nearly  ever}^  lake  and  pond,  and  even  by  ephemeral  pools  by  the  Ava3'side, 
but  is  especially  marked  in  great  seas  like  those  drained  by  the  St.  Law- 


40  LAKES    OF    NORTH    AINIERICA. 

rence.  During  storms,  all  of  the  streams  pouring  into  the  upper  Lauren- 
tian  lakes,  from  the  surface  drainage  of  the  land,  are  brown  and  heavy 
with  mud,  but  the  water  rushing  over  Niagara  remains  of  the  same  deep 
greenish-blue  tint  season  after  season  and  year  after  year.  Niagara  river, 
above  the  falls,  and  the  St.  Lawrence  are  surface  streams,  because  their 
clear  waters  have  but  slight  power  of  corrasion ;  it  is  for  this  reason  that 
during  the  centuries  they  have  occupied  their  present  channels  they  have 
not  materially  deepened  them. 

In  the  case  of  lakes  fed  by  the  turbid  waters  from  glaciers,  the  part  they 
play  as  settling  basins  is  even  more  strikingly  shown  than  in  the  instances 
just  cited.  Lake  Geneva,  Switzerland,  fed  by  the  silt-laden  waters  of  the 
Rhone,  is  discolored  for  several  miles  from  where  the  river  enters,  but 
wlien  the  waters  leave  the  lake  and  again  start  on  their  journey  they  are 
wonderfully  clear.  An  abundance  of  similar  illustrations  are  furnished 
by  the  glacial-fed  lakes  of  the  Sierra  Nevada  and  Cascade  mountains  and 
by  some  of  the  numerous  lakes  on  the  head  waters  of  the  Yukon. 

The  streams  flowing  from  lakes  are  not  always  clear,  however,  as 
exceptions  occur  where  the  outlets  are  so  situated  that  shore  currents 
may  bring  sediment  to  them.  The  construction  of  beaches  and  embank- 
ments by  shore  currents  may  take  place  at  the  outlet  of  a  lake  so  as  to 
obstruct  the  escape  of  its  waters  and  initiate  a  struggle  between  the 
waters  tending  to  form  deposits  and  those  escaping  through  the  channel 
of  discharge.  The  outflowing  waters  may  thus  be  rendered  turbid  and 
have  the  material  supplied  with  which  to  erode  their  channels.  A  case 
in  point  is  thought  to  be  furnished  at  the  south  end  of  Lake  Huron, 
where  River  St.  Clair  has  its  source,  although  definite  observations  on 
the  relation  of  the  outlet  to  shore  currents  have  not  been  made.  The 
waters  of  River  St.  Clair  are  not  of  the  transparent  character  that  would 
be  expected  in  a  stream  starting  from  a  large  lake ;  and  a  broad  delta  has 
been  formed  in  Lake  St.  Clair,  into  which  the  river  empties  after  a  short 
course  through  low  alluvial  lands.  The  source  of  the  material  forming 
the  delta  cannot  be  referred  to  the  erosion  of  the  banks  of  the  stream,  and 
is  not  furnished  by  tributaries,  but  apparently  comes  from  the  action  of 
waves  and  currents  on  the  shores  of  Lake  Huron  adjacent  to  its  outlet.^ 

The  rapidity  with  which  lake  basins  in  all  parts  of  the  world  are 
becoming  filled  with  sediment  is  sufficient  in  itself  to  show  that  no  lakes 
fed  by  turbid  streams  can  be  geologically  old. 

1  These  conclusions  have  recently  bte  confii-med  by  F.  B.  Taylor  in  an  instractive  paper 
on  "  The  Second  Lake  Algouqum,"  Am.  Geol.,  vol.  15,  March,  1895,  pp.  171,  172. 


MOVEMENTS    OF    LAKE    WATERS.  41 

Mechanical  sediments.  —  The  coarse  sediment  brought  to  lakes  by- 
streams  is  either  built  into  deltas  or  swept  along  the  coast  by  shore  cur- 
rents and  mingled  with  the  pebbles  and  sand  derived  from  the  wear  of 
the  land  Ijy  shore  waves.  The  finer  products  of  the  wash  of  the  land, 
and  of  shore  erosion,  are  carried  lakeward  and  deposited  in  stratified  lay- 
ers over  the  lake  bottom.  In  general,  the  sheet  of  material  thus  spread  out 
is  thickest  and  coarsest  near  shore  and  becomes  finer  and  thinner  as  the 
distance  from  land  increases.  When  sedimentation  goes  on  uninterrupt- 
edly until  a  basin  is  filled,  the  result  is  a  more  or  less  regular  lens-shaped 
body  of  sediments,  having  a  broad  central  area  of  fine  material,  wliich 
graduates  into  a  fringe  of  coarser  character  about  its  borders.  The  coarse 
strata  in  the  shore  deposits  overlap  and  dovetail  along  their  lakeward 
margins,  with  the  outer  borders  of  the  layers  of  fine  sediment  in  the  cen- 
tral part  of  the  basin,  for  the  reason  that  the  coarser  material  is  carried 
farther  from  land  during  storms  than  when  the  weather  is  calm.  This 
general  relation  of  coarse  shore  and  fine  off-shore  deposits  is  of  interest, 
especially  in  the  study  of  extinct  lakes,  and  may  enable  one  to  draw  their 
former  boundaries  with  considerable  accuracy  even  when  all  distinctive 
features  of  their  shore  topography  have  been  obliterated. 

The  sediments  of  the  existing  lakes  of  America,  so  far  as  they  have 
been  studied,  are  principally  clays,  which  vary  in  character  according  to 
the  nature  of  the  rocks  and  soils  on  the  neighboring  land.  The  sediments 
of  the  Laurentian  lakes  and  of  lakes  generally,  particularly  in  humid 
regions,  are  characteristically  blue  clays.  The  Pleistocene  clays  of  the 
Erie  and  Ontario  basins  are  tenacious  blue  clays,  similar  to  those  now 
accumulating  in  the  same  basins;  but  the  clays  deposited  during  a 
former  broad  extension  of  Lake  Superior  are  fine,  evenly  laminated  pink- 
ish clays,  and  owe  their  distinctive  tint  to  the  color  of  the  rocks  from 
Avhich  they  were  derived. 

The  sediments  now  accumulating  in  the  lakes  of  the  arid  regions, 
but  more  especially  in  the  temporary  or  playa  lakes,  are  usually  light- 
colored,  and  have  a  yellowish  tint  when  dry. 

In  regions  of  deep  rock  decay,  like  the  southern  Appalachians,  the 
ddbris  swept  into  lakes  would  have  the  characteristic  tints  of  terra  ro^m, 
as  the  highly  oxidized  product  of  prolonged  rock  decay  is  termed,  unless 
it  was  mingled  with  organic  matter  in  sufticient  quantity  to  deoxidize 
the  iron  to  which  its  richness  of  color  is  due. 

The  e-eneralization  that  all  lake  sediments  are  of  a  reddish  tint,  for- 
merly  advanced  by  certain  English  geologists,  does  not  find  support  from 


42  LAKES    OF    NORTH    AMERICA. 

somewhat  extended  observations  made  in  this  connection  in  America. 
In  fact,  the  blue  and  yeUowish  tints  of  such  deposits  are  so  general  in  tliis 
country  that  the  reverse  of  the  proposition  referred  to  might  be  more 
reasonably  claimed. 

In  small  lakes,  when  sedimentation  is  retarded,  the  growth  of  mol- 
lusks,  diatoms,  etc.,  may  progress  ra,pidly  and  their  dead  shells  accumu- 
late on  the  bottom  so  as  to  exceed  the  amount  of  mechanical  sediment, 
and  shell  marl  and  diatomaceous  earth  be  formed.  This  process  is 
especially  well  marked  in  lakes  that  are  surrounded  hj  matted  vegetation 
through  which  the  inflow^ing  waters  percolate  and  are  filtered  of  nearly 
all  material  in  suspension.  As  the  growing  mosses  encroach  on  lakes  of 
this  character,  a  layer  of  peat  is  formed  above  the  marl  and  a  well-marked 
stratification  results.  Layers  of  peat  above  strata  of  shell  marl  may  Ije 
seen  in  process  of  accumulation  in  many  of  the  small  lakes  of  INIichigan 
and  other  similar  regions.  In  lake  and  swamp  deposits  that  are  now 
drained  and  utilized  for  farming  purposes,  a  layer  of  white  marl  beneath 
black  humus,  is  frequently  exposed.  These  deposits  have  an  additional 
interest  from  the  fact  that  we  find  in  them  the  bones  of  the  mastodon, 
mammoth,  giant  beaver  and  huge  sloth-like  animals  that  roamed  over 
North  America  in  recent  times,  but  are  now  extinct. 


CHAPTER    III. 

THE  TOPOGRAPHY  OF  LAKE   SHORES. 

The  variety  and  l)eauty  of  a  landscape,  embracing  mountains  and  hills, 
valleys  and  ravines,  is  mainly  due,  as  is  well  known,  to  the  action  of 
running  water.  Tlie  lines  resulting  from  this  mode  of  sculpture  are  more 
or  less  vertical.  The  waters  of  lakes  also  engrave  their  histories  on  the 
rocks,  but  the  writing  conforms  with  the  water  surface  and  is  in  horizontal 
bands.  Two  strongly  contrasted  types  of  relief  are  thus  produced,  ^^'hieh 
may  he  distinguished  at  a  glance.  The  details  in  each  type  may  be 
separated  and  their  mode  of  origin  explained.  Each  feature  of  the  land 
is  thus  found  to  have  a-  meaning,  and  the  pleasure  derived  from  even  the 
most  sublime  and  beautiful  lands.capes  is  vastly  enhanced  to  those  who 
can  read  their  histories. 

The  work  of  rain  and  rivers  is  outside  the  scope  of  the  present  book, 
but  the  principal  topogra})hic  features  characteristic  of  lake  shores  will  be 
briefly  described  and  their  mode  of  origin  indicated. 

The  sea  cliflf.  —  Usually  the  first  features  of  a  lake  shore  to  attract 
attention  are  the  steep  slopes  which  rise  from  the  water's  edge  and  seem 
to  mark  the  boundary  beyond  which  the  waves  cannot  pass.  That  the 
slopes  here  referred  to  have  been  produced  by  the  waters  of  the  lake  eat- 
ing into  the  land,  is  so  apparent  that  it  seems  almost  a  waste  of  words  to 
explain  the  process  by  which  they  are  formed.  Their  declivity  varies  accord- 
ing to  the  nature  of  the  material  forming  the  land  and  also  in  conformity 
with  atmospheric  conditions.  When  the  shores  are  of  soft  rock  or  loose 
unconsolidated  material,  the  slopes  are  gentle,  but  when  the  shore  is  of 
hard  rock  they  may  become  vertical  or  even  overhanging  precipices.  In 
regions  where  Aveatliering  is  progressing  actively,  the  waste  of  the  land, 
owing  to  the  com])ined  influences  of  rain,  frost,  etc.,  may  be  more  rapid 
than  the  erosion  of  a  lake  shore  by  waves  and  currents;  under  these  con- 
ditions the  bluffs  bordering  a  lake  will  have  a  more  gentle  slope  than 
where  atmos})heric  agencies  are  relatively  less  destructive.  The  name 
"  sea  cliff  "  is  applied  to  the  slopes  produced  by  the  under-cutting  of  lake 
shores  without  reference  to  their  declivity,  and  has  been  borrowed  from 


44  LAKES    OF    NORTH    AMERICA. 

the  nomenclature  of  the  oceanic  shores  where  topographic  forms  similar  in 
character  and  in  origin  exist  in  many  places  on  a  magnificent  scale.  Varia- 
tions in  the  appearances  of  sea  cliffs  in  soft  and  hard  material  are  shown  on 
Plates  8  and  9.  These  illustrations  have  beeil  selected  from  a  large  num- 
ber of  photographs  taken  by  the  writer  on  the  borders  of  the  Laurentian 
lakes,  and  illustrate  the  two  types  of  shore  features  there  most  pronounced. 
The  recession  of  sea  cliffs  may  be  best  studied  when  a  gale  is  blowing 
directly  on  shore.  At  such  a  time,  each  wave  as  it  reaches  shallow 
water  and  surges  up  on  the  land,  carries  forward  the  gravel  and  sand 
within  reach  and  dashes  it  against  the  base  of  the  cliff  and  tends  to 
wear  it  away.  The  finer  products  produced  by  the  friction  and  pounding 
of  the  loose  stones  against  each  other  and  against  the  cliff,  are  carried  lake- 
ward  by  the  under-tow,  leaving  the  coarser  fragments  ready  to  be  caught 
up  by  the  next  inrush  of  water  and  the  process  repeated.  As  the  cliff  is 
under-cut,  fresh  angular  fragments  fall  from  its  face  to  the  beach  below 
and  are  at  once  attacked  by  the  waves  and  sooner  or  later  reduced  to 
rounded  gravel  and  sand.  The  cliff  thus  furnishes  the  tools  for  its  own 
destruction. 

The  manner  in  which  lakes 

^^p    wear  away  the  land  confining- 

-'''^r  them  is  illustrated  in  the  fol- 

.j^fjTf..  *^fi!???-€ ^^^^^^  lowing  section  of  a  rocky  shore, 

^^^^^^  which  also  shows  the  relation 

,^^^^^^^^^^^^  of    the    sea    cliff    b  c    to    the 

platform  or  terrace'  a  c  at  its 

Fig.  2. —  Profile  of  a  Sea  Cliff  a>'d  Terrace.  •, 

Waves  are  only  able  to  reach  the  land  in  a  narroAv  vertical  interval, 
determined  mainly  by  the  difference  in  their  height  during  calm  weather 
and  when  storms  are  raging.  Even  in  the  case  of  large  lakes  this  inter- 
val does  not  exceed  ten  or  fifteen  feet,  and  on  account  of  the  debris 
usually  encumbering  the  shore,  the  actual  zone  of  erosion  on  the  fresh 
rock  surface  is  normally  very  much  less  than  this.  The  waves  thus  act 
like  a  horizontal  saw  cutting  into  the  land.  The  result  is  that  at  the 
base  of  every  sea  cliff  there  is  a  platform  or  terrace,  as  indicated  in  the 
above  diagram.  The  junction  of  the  sea  cliff  with  its  accompanying  ter- 
race is  a  horizontal  line,  determined  by  the  elevation  of  the  lake  surface. 

Lake  waters  unaided  by  debris,  like  the  waters  of  clear  streams,  have 
but  slight  power  to  erode.  It  is  only  when  the  margin  of  a  lake  is  suffi- 
ciently shallow  to  bring  the  debris  on  its  bottom  within  the  reach  of  the 


THE  TOPOGRAPHY  OF  LAKE  SHORES.  45 

waves  that  the  land  is  cut  away  so  as  to  form  sea  cliffs  and  terraces. 
This  is  shown  in  a  striking  manner  along  large  portions  of  the  shores  of 
Lake  Superior,  where  bold  cliffs,  an  inheritance  from  a  previous  topo- 
graphic cycle,  plunge  into  deep  water,  and  are  without  talus  slopes  or 
other  loose  deposits  within  reach  of  the  waves.  In  these  instances  there 
is  scarcely  a  mark  on  the  rocks  that  would  record  the  present  horizon  of 
the  lake  should  its  waters  be  withdrawn.  Clear  waters  may  dissolve  the 
rocks  against  which  they  dash,  however,  and  when  cliffs  of  limestone 
and  other  easily  soluble  rock  descend  into  deep  waters,  a  line  of  grottoes 
and  caves  may  be  formed  below  the  upper  wave  limit,  and  perliaps  increase 
until  a  shelf  is  produced  on  which  sand  and  pebbles  could  lodge.  When 
this  happens,  erosion  by  solution  is  assisted  by  mechanical  means,  slight  at 
first,  but  increasing  as  the  conditions  become  more  favorable,  until  cliffs 
and  terraces  result. 

Terraces.  —  The  terraces  about  the  hiargins  of  existing  lakes  are 
usually  covered  with  the  loose  stones  and  sand,  and  form  the  beaches  on 
which  one  may  walk  during  calm  weather. 

The  surface  of  a  typical  lake  terrace  slopes  gently  lake  ward  and  is 
bounded  on  the  landward  margin  by  the  upward  slope  of  the  accom- 
panying sea  cliff,  and  on  the  submerged,  lakeward  margin  by  a  down- 
ward slope  leading  to  deeper  water.  These  terraces  owe  their  formation 
to  excavation  or  to  deposition,  and  in  most  instances  the  two  processes 
are  combined.  Even  when  the  terrace  is  due  principally  to  excavation, 
there  is  a  surface  layer  of  rounded  debris  resting  on  it,  which  is  usually 
thickest  on  the  lakeward  margin  and  forms  the  lakeward  slope.  These 
features  are  shown  in  the  following  cross  section  of  a  lake  shore,  where  a 
compound  terrace  is  being  formed,  and  also  on  Plate  13. 


LAKE      SuarACE 


Fig.  3.  — Profile  of  a  cut  and  built  Terrace. 


On  precipitous,  rocky  shores,  terraces  are  not  produced,  for  the  reason 
already  stated  in  considering  the  origin  of  sea  cliffs,  that  the  debris  from 
the  land  falls  into  deep  water  below  the  reach  of  the  waves. 


46  LAKES    OF    NORTH    AMERICA. 

Reference  has  already  been  made  to  the  action  of  the  waves  when  the 
wind  blows  directly  on  shore.  The  return  current  is  then  an  undertow 
flowing  lakeward.  When  the  wind  blows  against  the  shore  at  a  low 
angle,  however,  currents  are  established  which  travel  along  the  lake 
margin  and  sweep  the  loose  material  on  the  surface  of  the  terrace  with 
them.  These  currents  have  many  of  the  features  of  streams,  and  greatly 
increase  the  j^ower  of  waves  to  erode  the  land.  The  upward  movement 
of  waves  tends  to  lift  loose  material  within  their  reach  and  the  lateral 
movement  of  currents  to  transjjoit  it.  The  loose  material  at  the  base  of 
sea  cliffs  is  thus  carried  along  the  beach  by  shore  currents  in  one  direction 
or  another,  according  to  the  direction  of  the  wind,  and  deposited  so  as  to 
form  accumulations  of  various  character. 

When  a  headland,  with  a  beach  at  its  base,  is  flanked  on  either  hand 
by  low  shores,  tlie  debris  falling  from  its  face  is  carried  along  by  the 
shore  currents  and  built  into  terraces  adjacent  to  the  land  or  deposited  so 
as  to  form  free  embankments  or  ridges,  at  some  distance  from  the  original 
shore.  That  this  process  is  of  common  occurrence  may  be  shown  on 
many  lake  margins  by  examining  the  material  forming  rocky  headlands 
and  comparing  it  with  the  stones  on  neighboring  beaches.  In  such  in- 
stances the  rock  fragments  at  the  base  of  the  cliff  will  frequently  be 
found  to  be  large  and  angular  and  to  become  smoother  and  more  and 
more  rounded  the  farther  they  are  traced  from  their  parent  ledges. 

Terraces  and  marginal  embankments,  built  wholly  of  gravel  and  sand, 
may  also  be  formed  on  low  shores  by  the  washing  up  of  loose  material 
from  this  lakeward  margin,  thus  deepening  the  water  on  the  outside  of 
the  shelf. 

The  transportation  of  debris  along  the  surfaces  of  terraces  by  the  com- 
bined action  of  waves  and  currents,  and  its  deposition  when  deep  water  is 
reached,  leads  to  the  formation  of  structures  of  various  forms,  known  as 
embankments. 

Embankments.  —  This  name  has  been  adopted  for  free  ridges  of 
loose  material  built  by  currents  about  the  margins  of  water-bodies.  They 
have  the  general  form  of  railroad  embankments,  and  their  level  crests  in 
most  instances  rise  from  a  few  inches  to,  perhaps,  three  or  four  feet  above 
the  calm-weather  surfaces  of  the  water  in'  which  they  occur.  The  ten- 
dency of  built  terraces  to  change  to  embankments  on  low  shores  has  already 
been  noticed,  but  the  most  typical  examples  occur  where  shore  currents, 
having  an  abundance  of  loose  material  at  their  command,  are  deflected 


o       >. 


o     - 


THE  TOPOGRAPHY  O^'  LAKE  SHORES. 


47 


into  deep  water  and  thus  lose  their  power  to  transport.  The  variations 
in  the  shapes  of  embankments  have  led  to  the  recognition  of  various  more 
or  less  specific  forms,  such  as  spits,  loops,  bars,  V-bars,  etc.,  some  of  which 
are  described  below. 

The  building  of  embankments  can  be  best  studied  where  there  is  an 
abrupt  change  in  the  direction  of  the  shore  adjacent  to  a  locality  where 
the  formation  of  a  sea  cliff  and  its  accompanying  terrace  is  in  progress. 
Such  an  instance  is  illustrated  in  the  following  sketch-map  : 


Fig.  4.  —  SivETcn-MAP  of  an  Emb.vnkment. 


The  shore  on  the  right  of  the  cove  is  steep  and  forms  a  sea  cliff  that  rises 
above  a  terrace  along  which  the  current  travels  in  the  direction  indicated 
by  an  arrow.  Shore  currents  follow  the  broader  outlines  of  the  land,  but 
cut  across  bays  and  inlets.  For  this  reason,  in  the  case  before  us,  the 
sand  and  gravel  swept  along  the  surface  of  the  terrace  is  carried  into 
deep  waters  and  is  deposited  when  the  direction  of  the  shore  changes 
abruptly,  as  the  flow  of  the  water  is  then  checked.  The  terrace  is  pro- 
longed as  an  embankment,  having  the  same  level,  and  is  lengthened  by 
material  carried  along  its  surface  and  deposited  at  its  distal  extremity. 
The  construction  of  such  an  embankment  is  analogous  to  the  manner 
in  which  railroad  embankments  are  made  by  carting  dirt  along  them 
from  a  cut  and  dumping  it  at  the  end  of  the  unfinished  structure.  In 
cross  sections  an  embankment  shows  a  more  or  less  perfect  arching  of  the 
material,  and  forming  what  may  be  termed  an  "  anticlinal  of  deposition." 

In  the  ideal  illustration  here  presented,  it  is  evident  that  a  continu- 
ation of  the  process  would  result  in  the  prolongation  of  the  embankment 
until  it  touched  the  shore  at  the  left  of  the  bay.  The  outline  of  the  lake 
would  then  be  simplified  and  a  lagoon  formed  behind  the  embankment. 
Should  a  stream  enter  such  a  lagoon,  the  water  escaping  from  it  might 
keep  a  channel  open  to  the  lake,  but  a  struggle  would  ensue  between  the 
shore  currents  tending  to  close  the  break  and  the  outflowing  water 
striving  to  keep  it  open.  Eddies  in  the  conflicting  currents  would  result 
and  lead  to  changes  in  the  outlines  of  the  embankment. 


48 


LAKES    OF    NORTH    AMERICA. 


When  a  structure  like  that  descrilied  above  is  incomplete  and  projects 
from  the  shore  like  an  unlinished  railroad  embankment,  it  is  teimed  a  sint. 
An  illustration  of  such  an  instance  observed  on  the  shore  of  An  Train 
island.  Lake  Superior,  is  shown  in  Plate  11.     See  also  Plates  2,  3  and  4. 

When  an  embankment 
spans  the  entrance  of  a  bay 
so  as  to  shut  it  off  more  or 
less  completely  from  the 
main  Avater  body,  it  is 
termed  a  har^  in  accord- 
ance with  the  custom  of 
mariners  in  designating 
such  obstructions  to  navi- 
gation. Maps  of  bars  on 
the  shores  of  lakes  Su- 
j)erior  and  Ontario  are  re- 
l^roduced  in  Figs.  5  and 
VSjgc^''^, ' /' ^  •  \ '^  6,   from   the   maps  of  the 

*    '     "    '  U.  S.  Lake  Survey.     The 

manner  in  which  these 
were  formed,  as  well  as 
their  various  modifications 
of  outline  and  the  presence 
of  channels  across  them  in  certain  instances,  will  be  understood  from  the 
description  of  a  more  simple  example  just  given. 

The  end  of  a  spit  is  frequently  turned  toward  the  shore,  owing  to  a 
deflection  of  the  current  that  built  it.  or  to  the  opposing  action  of  two 
or  more  currents,  and  becomes  a  hook,  as  is  illustrated  on  Plate  12. 
Again,  where  the  hook  is  more  jjronounced  and  the  distal  end  of  the 
structure  touches  the  shore,  as  happens  occasionally  when  there  are  only 
slight  changes  in  the  direction  of  the  coast  line,  a  Joop-har  or  V-har  results. 
In  brief,  it  may  be  said  that  the  waves  and  currents  of  lakes  have 
the  power  of  excavating  cut  terraces  along  the  shores  confining  them  and 
of  carrying  away  the  waste  from  the  cutting,  together  with  similar  mate- 
rial contributed  by  streams,  and  of  liuilding  it  into  terraces  and  embank- 
ments of  various  forms  adjacent  to  neighl)oring  shores. 


Fig.  5. — Map  of  sand  bars:  west  end  of  Lake  Supeiuok. 


Deltas. — Where  streams  bring  to  a  lake  more  detritus  than  is  carried 
away  by  shore  currents,  accumulation  takes  place  and  an  addition,  termed 


THE  TOPOGRAPHY  OF  LAKE  SHORES. 


49 


a  delta,  is  made  to  the  land.  The  most  instructive  deposits  of  this  nature 
occur  where  high  grade  streams  enter  a  lake,  as  when  a  lake  washes  the 
base  of  a  mountain  range.  In  such  an  instance,  pebbles  and  water-worn 
boulders  are  swept  along  by  the  stream  until  it  mingles  with  the  quiet 
lake  water,  where  its  velocity  is  checked  and  the  coarser  portion  of  its 


Fig.  g,  —  Map  of  saxd  bars  :  Sorxii  shore  of  Lake  <3xtario. 


load  dropped ;  fine  sand  is  carried  beyond  and  deposited  about  the  outer 
margin  of  the  accumulation  of  boulders  and  pebbles,  and  the  finer 
material  held  in  suspension  is  transported  still  farther  from  shore  and  dis- 
tributed over  the  lake  bottom.  The  coarse  material  is  deposited  about 
the  mouth  of  the  stream  in  a  semi-circular  pile,  the  base  of  which  is 
beneath  the  water  and  the  apex  some  distance  above,  where  the  stream 
begins  to  lose  velocity.  The  pile  is  built  out  in  all  directions  in  Avhich  the 
water  has  freedom  to  flow,  and  a  semi-circular  or  occasionally  a  truly 
delta-shaped  addition  is  made  to  the  land. 

Fine  examples  of  deltas,  built  by  swift  streams  adjacent  to  a  precipi- 
tous shore,  occur  on  the  west  side  of  Seneca  lake,  New  York,  near  Wat- 
kins.  In  these  deltas  the  action  of  shore  currents  from  both  the  north 
and  south  is  conspicuous,  and  the  deposits  have  been  cut  away  so  as  to 
leave  a  triangular  or  markedly  delta-shaped  outline,  but  the  apex  of  each 
"  delta "  points  lakeward,  instead  of  toward  the  shore  as  is  the  normal 


50  LAKES    OF    NORTH    AMERICA. 

condition.  About  the  margins  of  these  deltas  there  are  small  gravel  bars 
that  are  frequentl}-  looped  and  enclose  lagoons.  An  active  struggle  is 
there  in  progress  between  the  onttlowing  streams  and  the  shore  currents, 
which  has  modified  the  form  of  the  deltas  in  the  peculiar  way  just 
referred  to. 

A  delta  advances  as  fresh  material  is  added  to  its  outer  margin,  and 
at  the  same  time  the  apex  of  the  pile  rises  and  slowly  migrates  up  stream. 
Such  a  deposit  has  a  well-defined  structure,  due  to  its  mode  of  growth. 
A  radial  section  made  from  its  apex  to  any  point  on  its  periphery  would 
show  three  divisions,  as  is  indicated  in  the  following  sketch  section  of  a 
delta  built  in  Lake  Bonneville,  at  Logan,  Utah. 


Fig.  7.  —  Sectiox  of  a  Delta. 


The  history  to  be  read  in  such  a  section  is  this:  the  fine,  evenly  strati- 
fied beds  beneath  the  coarse  inclined  layers  are  sediments  deposited  on 
the  lake  bottom,  but  about  the  margins  of  deltas  they  are  usually  thicker 
than  on  neighl:)oring  lakeward  areas,  owing  to  more  rapid  depositions 
from  the  waters  of  the  delta-forming  stream.  In  some  instances  a  broad, 
low  apron-like  deposit  of  fine  sediment  is  formed  about  the  lakeward 
margin  of  the  delta  proper.  As  the  coarser  portion  of  a  delta  increases,  it 
advances  lakeward  and  covers  the  layers  of  fine  sediment  previously  laid 
down,  and  frequently  causes  them  to  become  folded  and  wrinkled  and 
occasionally  l)roken  and  faulted,  on  account  of  the  weight  of  material 
imposed  upon  them. 

•The  boulders,  gravel  and  sand  brought  down  by  a  stream  are  carried 
to  the  outer  margin  of  its  delta,  and  roll  and  slide  down  its  submerged 
lakeward  slope  so  as  to  form  inclined  layers.  The  angle  of  inclination 
of  these  layers  is  the  angle  of  stability  in  water  of  the  material  forming 
them.  Where  the  deposit  is  mainly  of  rounded  stone  and  gravel,  the 
angle  of  slope  is  in  the  neigliborhood  of  30  to  35  degrees,  but  in  some 
instances  is  steeper  and  the  structures  are  unstable  and  favorable  for 
landslides. 

The  triangular  area  shown  in  the  section,  above  the  inclined  beds,  is 
the  subaerial  portion  of  the  delta,  built  by  the  stream  in  meandering 


THE  TOPOGRAPHY  OF  LAKE  SHORES.  51 

over  its  surface.  It  is  really  an  alluvial  cone,  similar  to  the  conical  piles 
of  debris  so  common  in  desert  valleys  at  the  mouths  of  high  grade  cailons. 
It  is  irregularly  stratified,  the  layers  being  inclined  at  a  Ioav  angle  corre- 
sponding with  the  slope  of  the  surface  of  the  structure  at  the  time  they 
were  laid  down. 

The  change  from  the  gently  sloping  and  irregularly  bedded  material 
of  the  alluvial  portion  or  cap  of  the  delta,  to  the  steeply  inclined  and  more 
regularly  bedded  layers,  marks  the  level  of  the  lake  in  which  the  deposit 
was  formed.  The  outer  margin  or  periphery  of  the  delta,  is  in  a  horizon- 
tal plane  and  retains  the  same  position  as  the  delta  advances,  providing 
there  is  practically  no  change  in  the  level  of  the  lake  surface.  The  surface 
slope  of  the  cap  of  the  delta,  along  radial  lines  from  the  apex  to  the  periph- 
ery, is  gently  concave  to  the  sky.  On  recent  examples  the  surface  is 
frequently  scored  with  radiating  and  branching  channels,  or  "distribu- 
taries," left  by  the  changeable  stream  that  built  the  structure.  As  a 
delta  increases  in  size  its  apex  rises  and  slowly  migrates  up  stream,  as 
alread}^  stated,  so  that  in  large  deltas  of  high-grade  streams  the  apex  is 
frequently  well  within  the  mouth  of  the  canon  through  which  the  drain- 
age is  delivered. 

In  the  deltas  of  low-grade  streams,  like  the  Mississippi,  the  divisions 
noted  above  are  not  readily  distinguishable,  as  the  material  forming  them 
is  fine  throughout  and  the  inclination  of  all  the  layers  is  gentle. 

Should  the  surface  of  a  lake  be  lowered  after  having  stood  at  a  definite 
horizon  for  a  long  period,  the  terraces,  embankments,  deltas,  etc.,  formed 
about  its  borders  become  conspicuous  features  of  the  exposed  land  surface 
and  another  series  of  similar  forms  is  at  once  begun  at  a  lower  level. 
Should  another  subsidence  follow,  another  series  of  horizontal  lines  will 
be  added  to  the  topography  of  the  shores.  A  rise  of  a  lake  causes 
the  submergence  of  previously  formed  shore  features,  and  they  may  be- 
come covered  with  fine  sediment  or  have  other  wave  and  cunent-l)uilt 
structures  imposed  upon  them.  Such  changes  lead  to  puzzling  compli- 
cations in  the  records,  as  has  been  observed  in  many  instances  where  lake 
basins  have  been  emptied  and  their  sides  and  bottoms  laid  bare. 

Ice-built  walls.  —  In  addition  to  the  topographic  features  character- 
istic of  lake  shores  thus  far  noticed,  there  are  others  due  to  the  action  of 
ice.  In  northern  latitudes  the  formation  of  sea  cliffs,  terraces,  embank- 
ments, etc.,  about  the  margins  of  lakes,  excepting  those  of  large  size, 
takes  place  mainly  in  the  summer  season.      In  winter,  when  most  small 


62  LAKES    OF    NORTH   AMERICA. 

lakes  are  frozen  over,  the  expansion  of  tlie  ice  pushes  up  stones  and 
gravel  along  shelving  shores  and  forms  other  topographic  features. 
Another  process  tending  in  part  in  the  same  direction  comes  into  play 
in  the  spring  wlien  the  ice  on  a  lake  becomes  broken  and  is  moved 
by  the  wind.  The  action  under  these  conditions  is  the  same  that  takes 
place  on  a  much  larger  scale  on  the  shores  of  Labrador  and  other 
northern  lands,  where  an  ice  pack  is  driven  on  a  shelving  beach  by 
the  force  of  the  wind.  Stones  and  boulders  are  carried  up  low  lake 
shores,  in  the  manner  here  'noted,  and  added  to  the  ridge  formed  by 
the  winter  expansion  of  the  ice.  Occurrences  of  this  character  have 
been  observed  by  J.  l3.  Tyrroll  on  tlie  shore  of  Lake  Winnipegasie.^  In 
some  instances  these  ice-built  ridges  are  so  marked  and  appear  so  much 
like  artificial  walls  that  they  are  commonly  referred  to  the  work  of  man. 
In  some  observed  examples  in  the  northern  portion  of  the  United  States 
and  in  Canada,  ice-built  ridges  occur  40  to  50  feet  from  the  water's  edge, 
are  20  feet  high  and  broad  enough  to  furnish  convenient  roadways. 

The  formation  of  ice-lmilt  walls  about  the  margins  of  small  northern 
lakes  by  ice  expansion  was  first  explained  by  C.  A.  White.^  The  process 
has  also  been  clearly  stated  by  Gilbert,^  in  his  treatise  on  the  topography 
of  lake  shores,  from  which  the  following  is  quoted :  — 

"  The  ice  on  the  surface  of  a  lake  expands  while  forming  so  as  to 
crowd  its  edge  against  the  shore.  A  further  lowering  of  temperature 
produces  contraction,  and  this  ordinarily  results  in  the  opening  of  ver- 
tical fissures.  These  admit  the  water  from  below  and  by  the  freezing  of 
that  water  are  filled,  so  that  when  expansion  follows  a  subsequent  rise 
of  temperature  the  ice  cannot  assume  its  original  position.  It  conse- 
quently increases  its  total  area  and  exerts  a  second  thrust  upon  the  shore. 
When  the  shore  is  abrupt  the  ice  itself  yields,  either  by  crushing  at  the 
margin  or  by  the  formation  of  anticlinals  (upward  folds)  elsewhere ;  but 
if  the  shore  is  gently  shelving,  the  margin  of  the  ice  is  forced  up  the 
declivity  and  carries  witli  it  any  boulders  or  other  loose  material  aljout 
which  it  may  have  frozen.  A  second  lowering  of  temperature  does  not 
withdraw  the  protruded  ice  margin,  but  initiates  other  cracks  and  leads 
to  a  repetition  of  the  shoreward  thrust.  The  process  is  repeated  from 
time  to  time  during  the  winter,  but  ceases  with  the  melting  of  the  ice  in 
the  spring.     The  ice  formed  the  ensuing  winter  extends  only  to  the  water 

1  Geol.  and  Nat.  Hist.  Surv.  of  Canada.     Ann.  Rep.,  1890-91,  p.  04  B. 

2  American  Naturalist,  vol.  2,  1869,  pp.  140-149. 
8  Fifth  Ann.  Rep.,  U.  S.  Geol.  Surv.,  p.  109. 


THE  TOPOGRAPHY  OF  LAKE  SHORES.  53 

margin,  and  by  the  winter  s  oscillation  of  temperature  can  be  thrust  land- 
ward only  to  a  certain  distance,  determined  by  the  size  of  the  lake  and 
the  local  climate.  There  is  thus  for  each  locality  a  definite  limit  Ijeyond 
which  the  projection  of  Ijoulders  cannot  Ije  carried,  so  that  all  are  de- 
posited along  a  common  line  where  they  constitute  a  ridge  or  wall." 

Shore  walls  are  not  conspicuous  about  the  margin  of  large  lakes  for 
the  reason  that  they  seldom  freeze  over  and  also  because  the  winter's  ice 
work  is  usually  obliterated  by  the  more  active  waves  and  currents  at 
other  seasons.  They  are  not  formed  about  deep  lakes  for  the  reason  that 
such  water  bodies  do  not  become  ice-covered,  and  for  the  same  reason 
they  do  not  occur  in  warm  climates. 

In  this  brief  sketch  of  the  topography  of  lake  shores,  an  attempt  has 
been  made  to  direct  attention  to  the  main  processes  by  which  the  results 
have  been  reached,  and  to  describe  briefly  the  character  of  some  of  the 
more  striking  forms  produced,  without  attempting  an  exhaustive  analysis 
of  the  subject.  To  the  reader  who  would  go  farther  in  the  studies  here 
outlined,  I  most  heartily  recommend  G.  K.  Gilbert's  attractive  paper  on 
the  topography  of  lake  shore,  in  the  5th  Annual  Report  of  the  U.  S.  Geo- 
logical Survey,  and  the  more  special  volume  by  the  same  author  on  Lake 
Bonneville,  forming  ^Monograph  No.  1  of  the  publications  of  the  U.  S. 
Geological  Survey. 


CHAPTER    IV. 
RELATION    OP    LAKES    TO    CLIMATIC    CONDITIONS. 

Lakes  may  be  conveniently  divided  into  two  great  classes,  fresh  and 
saline,  in  reference  to  the  chemical  composition  of  their  waters.  These 
two  classes  have  no  sharply  defined  boundary  betAveen  them,  but  a  com- 
plete graduation  may  be  found  between  the  freshest  and  most  saline 
examples. 

A  convenient  test  for  determining  to  which  class  a  lake  should  be 
referred  is  to  taste  its  water.  If  no  saline  or  alkaline  taste  is  perceptible, 
it  evidently  falls  in  the  first  class;  but  if  the  presence  of  salts  can  be 
determined  in  this  way,  it  should  be  referred  to  the  second  class. 

It  is  frequently  convenient,  however,  to  recognize  an  intermediate 
class,  or  brackish-water  lakes,  to  include  water  bodies  that  are  slightly 
saline  or  alkaline  to  the  taste,  but  contain  only  a  small  fraction  of  one 
per  cent  of  mineral  matter  in  solution. 

The  more  pronounced  differences  in  chemical  composition,  shown  by 
lakes,  depend  mainly  on  climatic  conditions.  Fresh  water  lakes  overflow 
or  else  their  surplus  water  escapes  by  percolation,  while  saline  lakes  are 
without  outlets.  Exceptions  to  this  rule  may  occur,  but  they  are  accom- 
panied by  unstable  conditions,  and  the  preseHce  of  an  outlet  to  a  saline 
lake  or  its  absence  in  the  case  of  a  fresh  lake,  are  temporary  phases  that 
have  not  continued  long  enough  to  bring  about  the  changes  toward 
which  they  tend. 

Fresh  lakes  occur  principally  in  humid  regions,  while  saline  lakes, 
with  the  exception  of  those  formed  by  the  isolation  of  bodies  of  sea 
water,  are  confined  to  regions  of  small  rainfall.  Whether  a  lake  shall 
overflow  or  not,  depends  ordinarily  on  the  relation  of  the  rainfall  over  its 
hydrographic  liasin  to  evaporation  from  the  lake  surface.  As  lakes  fre- 
([uently  receive  the  water  of  fissure  springs,  the  sources  of  which  may  be 
far  distant,  it  will  be  more  exact  to  say  that  whether  a  lake  held  in  an 
impervious  basin  shall  overflow  or  not,  depends  on  the  ratio  of  the  amount 
of  water  contributed  to  it  to  the  amount  evaporated  from  its  surface.  If 
the  inflow  is  in  excess  of  evaporation,  the  water  will  rise  and  its  area 
increase  until  an  equilibrium  is  established  or  until  an  outlet  is  found. 


RELATION    OF    LAKES    TO    CLIMATIC    CONDITIONS.  55 

When  evaporation  counterbalances  the  inflow  for  a  long  i)erio(I,  the 
waters  are  concentrated  and  become  charged  with  mineral  matter,  for  the 
reason  that  all  streams  and  springs  contain  foreign  substances  in  solution 
which  are  left  when  evaporation  takes  place. 

It  has  been  found  by  observation  that  in  regions  where  the  topographic 
conditions  are  favorable,  a  rainfall  of  al^out  20  inches  per  year,  and  an 
evaporation  ivom  lake  surfaces  in  excess  of  50  inches  per  year,  is  fre- 
quently accompanied  by  the  formation  of  lakes  that  do  not  rise  suthciently 
to  find  an  outlet.  When  the  difference  in  the  direction  indicated  between 
precipitation  and  evaporation  is  still  greater,  or  when  the  area  from  which 
a  lake  receives  the  drainage  is  small  in  reference  to  the  area  where  a  lake 
would  naturally  form,  desiccation  may  be  complete  and  permanent  lakes 
rendered  impossil>le. 

Whether  a  lake  shall  be  fresh  or  saline  depends,  therefore,  on  climatic 
conditions  and  on  the  configuration  of  its  hydrographic  basin. 

Fresh  Lakes. 

Material  in  Solution.  —  As  all  fresh  lakes  may  be  considered  as 
the  expansions  of  streams,  their  chemical  composition  is  indicated  where 
the  actual  lake  waters  have  not  been  analyzed,  by  the  composition  of  the 
streams  flowing  to  or  from  them.  It  follows,  therefore,  that  the  average 
composition  of  the  waters  of  fresh  lakes  Avould  be  shown  with  consider- 
ate accuracy,  l)y  the  average  composition  of  the  princi})al  rivers  in  the 
region  where  they  occur. 

Analyses  of  the  waters  of  20  of  the  principal  rivers  of  the  United 
States  have  shown  that  they  contain  on  an  average  0.15044  part  pt'r 
thousand  of  total  solids  in  solution,  of  which  0.05641G  part  per  thousand 
is  calcium  carbonate.  This  niay  l^e  taken  as  the  average  composition  of 
the  fresh  lakes  of  this  countr}-,  but  more  particularly  of  those  in  the 
humid  regions. 

In  a  table  of  48  analyses  of  European  river  waters  given  in  Biscliof's 
Chemical  Geology,  the  average  of  total  solids  in  solution  is  0.2127  and 
the  average  of  calcium  carbonate  0.1139  part  per  thousand.  From  tlic 
analyses  of  the  waters  of  36  European  rivers  given  in  lioth's  Chemical 
Geology,  including  some  of  those  mentioned  Ijy  Bischof,  the  average  of 
total  solids  is  0.2033  and  of  calcium  carl)f)nate  0.09598  part  per  thousand. 

In  both  American  and  European  rivers,  as  determined  from  the  above 
data,  the  average  of  total  solids  in  solution  is  0.1888  and  of  calcium  car- 


56  LAKES  OF  NORTH  AMERICA. 

bonate  0.088765  part  per  thousand.  These  figures  may  be  safely  as- 
sumed to  represent  the  average  amount  of  impurities  carried  by  normal 
streams,  and  consequently  indicate  the  character  of  the  lakes  to  or  from 
which  they  flow.  The  drainage  in  mountainous  regions,  especially  where 
supplied  by  melting  snow  and  ice,  may  be  purer  than  these  figures  indi- 
cate ;  while  in  arid  regions,  where  efflorescent  salts  frequently  whiten  the 
surface,  the  streams  are  more  highly  charged  with  saline  matter  than  when 
the  rainfall  is  abundant.  It  is  to  be  observed  that  material  carried  by 
streams  in  suspension  is  not  included  in  the  above  considerations. 

The  reader  may,  perhaps,  conclude  from  the  figures  just  given  that 
the  percentage  of  saline  matter  carried  in  solution  by  ordinary  streams  is 
unimportant  and  of  but  little  significance  in  connection  with  the  study 
of  lakes.  It  is  true  that  the  amount  of  foreign  matter  in  solution  in  a 
few  gallons  of  river  water  is  small,  but  where  the  volume  of  rivers  is  con- 
sidered the  amount  of  solid  substances  carried  by  them  in  solution,  even 
in  a  single  ^-ear,  becomes  truly  startling.  Knowing  the  volume  of  a 
stream  and  the  percentage  of  mineral  matter  it  contains,  one  can  readily 
compute  the  weight  of  the  matter  it  carries  in  solution  in  a  definite  time. 
This  computation  has  been  made  for  a  few  American  rivers.^ 

The  average  flow  of  Croton  river,  New  York,  is  400,000,000  gallons 
daily.  In  this  volume  of  water  there  are  183  tons  of  mineral  matter  in 
solution,  of  which  47  tons  are  calcium  carl)onate. 

The  Hudson  carries  daily  about  4,000  tons  of  matter  in  solution,  of 
which  more  than  1,200  tons  are  calcium  carbonate. 

The  Mississippi  carries  to  the  Gulf  of  jNIexico  in  a  single  year  about 
113  million  tons  of  mineral  matter  in  solution,  of  which  over  50  million 
tons  are  calcium  carbonate. 

These  estimates  are  only  approximately  correct  as  they  depend  in 
most  instances  on  a  single  analysis  and  on  a  small  number  of  measure- 
ments of  volume. 

The  invisible  loads  carried  liy  rivers  are  not  only  of  interest  in  con- 
nection with  the  study  of  lakes,  more  especially  of  saline  lakes,  but  open 
a  wide  field  of  research  in  reference  to  the  chemical  denudation  of  the 
land,  the  composition  of  ocean  waters,  and  the  source  of  the  material, 
more  particularly  of  the  calcium  carljonate,  secreted  by  marine  plants  and 
animals.  Into  this  broader  domain,  however,  to  which  our  subject  leads, 
we  may  not  now  enter. 

1  The  data  from  which  the  facts  here  stated  were  obtained,  as  well  as  similar  information 
concerning  other  streams,  is  given  m  Monograph  No.  11,  U.  S.  Geol.  Surv.,  pp.  172-175. 


relation  of  lakes  to  climatic  conditions.  57 

Types  of  Fresh  Lakes. 

Of  the  tens  of  thousands  of  fresh  hikes  scattered  over  North  America, 
and  especially  abundant  in  the  previously  glaciated,  northeastern  por- 
tion of  the  continent,  or  forming  a  part  of  the  more  impressive  scenery 
of  the  Cordilleran  region,  many  might  be  selected  as  types.  Atten- 
tion will  be  confined,  however,  to  the  Great  Lakes,  drained  by  the  St. 
Lawrence,  Lake  Tahoe,  California,  and  Lake  Chelan  in  the  State  of 
Washington. 

Tlie  Laiirentian  lakes.  —  The  group  of  great  lakes  drained  by  the 

St.  Lawrence,  as  is  well  known,  contain  the  most  magnificent  examples 
of  fresh  water-bodies  now  existing  on  the  earth.  Lake  Superior  still 
retains  its  position  as  the  largest  sheet  of  fresh  water  known,  although 
the  more  recent  discovery  of  Lake  Victoria  N3'anza  has  brought  a  rival 
into  the  field.  This  African  lake  is  estimated  to  have  an  area  of  about 
18,000  square  miles,  which  is  12,000  square  miles  less  than  the  area  of 
the  great  American  lake ;  but  when  an  actual  survey  shall  have  been 
made,  it  is  possible  that  this  difference  will  be  materially  decreased. 

While  Lake  Superior  exceeds  all  other  fresh  lakes  in  extent,  it  ranks 
second  among  terrestrial  water-bodies,  for  the  reason  that  the  Caspian 
Sea  is  the  largest  sheet  of  water  not  in  open  communication  with  the 
ocean,  now  existing.  The  Caspian  is  saline,  however,  and  falls  in  the 
second  grreat  division  of  lakes  here  recognized. 

The  origin  of  the  basins  of  the  Laurentian  lakes  has  been. referred  to 
in  Cliapter  I.  in  connection  with  the  action  of  glacial  agencies  in  obstruct- 
ing drainage ;  an  account  of  their  past  history  is  given  in  advance  in  cUs- 
cussing  the  Pleistocene  lakes  of  the  same  region ;  at  present  attention 
will  be  confined  to  some  of  the  more  interesting  features  of  the  existing 
lakes. 

The  U.  S.  Lake  Survey.  —  A  survey  of  the  Laurentian  lakes  was 
made  by  the  Corps  of  Engineers,  L".  S.  Army,  between  1841  and  1881, 
and  is  known  as  the  U.  S.  Lake  Survey.^  On  the  maps  or  chart  published 
by  that  survey,  the  outlines  of  the  shores  of  the  lakes  and  of  their  con- 
necting waters  are  given,  together  with  the  topography  of  a  narrow  strip 
of  the  adjacent  land ;   the  depth  of  water,  character  of  bottom,  etc.,  as 

1  Report  upon  the  Primary  Triangulation  of  the  U.  S.  Lake  Survey,  by  Lieut.-Col.  C.  B. 
Comstock,  Washington,  1882. 


58 


LAKES    OF    NORTH    AMERICA. 


determined  from  thousands  of  soundings,  is  also  indicated.  This  excellent 
survey  is  the  basis  of  nearly  all  accurate  information  now  accessible  con- 
cerning the  physical  features  of  the  lakes  in  question,  and  has  been  freely 
used  in  compiling  the  following  statements. 

Owing  to  changes  in  the  rivers  connecting  the  various  Laurentian 
lakes  and  in  bays  and  navigal^le  channels,  and  also  on  account  of  the 
many  harbor  and  canal  improvements  tliat  have  been  made,  a  new  survey 
of  portions  of  these  lakes  has  been  found  necessary,  and  is  now  in  prog- 
ress under  the  direction  of  Gen.  ().  M.  Poe. 

The  area  of  the  Laurentian  lakes  has  been  determined  with  approxi- 
mate accuracy  from  measurements  made  on  the  maps  of  the  U.  S.  Lake 
Survey.  The  results  of  these  measurements  by  different  individuals 
varv  somewhat,  but  those  published  by  L.  Y.  Schermerhorn^  are  here 
adopted. 

Area  of  the  Laurentiax  Lakes  ix  Square  Miles. 


Water  Sur- 

FAt'E. 


Water  Shed. 


Hybrographic 
Basin. 


Lake  Superior 

St.  ]\Iary's  river 

Lake  ^Michigan 

Lake  Huron  and  Georgian  Bay 

St.  Clair  river 

Lake  St.  Clair 

Detroit  river 

Lake  Erie 

Niagara  river 

Lake  Ontario       ...... 

Total .     . 


31,200 

150 

22,4.50 

23,800 

25 

410 

25 

9,960 

15 

7,240 


51,600 
800 

37,700 

31,700 
3,800 
3,400 
1,200 

22,700 
300 

21.600 


82,800 
9.50 

60,150 

55,500 
3,825 
3.810 
1,225 

32,660 
315 

28,840 


95.275 


174,800 


270.075 


The  volume  of  water  flowing  through  the  rivers  draining  the  various 
lakes  is  on  an  averao-e  as  follows : 


St.  Clary's  river,  the  outlet  of  Lake  Superior 

St.  Clair  river,  the  outlet  of  Lakes  Huron  and  Michigan 

Niagara  river,  the  outlet  of  Lake  Erie 

St.  LawTence  river,  the  outlet  of  Lake  Ontario 


CiTBic  Feet 
PER  Second. 
86,000 
235,000 
265,000 
300.000 


1  "Physical  Features  of  the  Northern  and  Northwestern  Lakes,"  Amer.  Jour.  Sci.,  3d 
sec,  vol.  33,  1887,  pp.  278-284. 


RELATION    OF    LAKES    TO    CLIMATIC    CONDITIONS. 


59 


The  mean  elevation  of  the  surfaces  of  the  Laurentian  lakes  above  the 
sea,  their  maximum  depth,  etc.,  as  shown  by  soundings,  are  as  follows  : 

Meax  Elevation  and  Maximum  Depth,  etc.,  of  the  Laurentiax  Lakes. 


jNIean  Eleva- 

TIOX. 

Approximate 
IVlEAN  Depth. 

maximum        ^^'^^™  '"■ 

DEPTH.                 ^^^''^   J^^-^"^ 

Sea  Level. 

Lake  Erie 

Lake  Iliiron      .... 
Lake  ^Michigan      .     . 
Lake  Ontario    .... 

Lake  Superior  .... 

^                               It 

573 
581 
581 
247 
602 

70 
250 
325 
300 
475 

210 

730          1           149 

870                    289 

738                    491 

1,008         i          400 

The  average  discharge  of  the  lakes  is  stated  by  Schermerhorn  to  be 
double  that  of  the  Ohio  and  nearly  equal  to  one  half  the  discharge  of  the 
Mississippi.  The  area  of  the  Laurentian  basin  is  a  third  larger  than  the 
hydrographic  basin  of  the  Ohio,  or  aljout  a  fifth  of  the  combined  areas 
of  the  basins  of  the  jNIississippi  and  its  affluents.  The  outflow  of  the  St. 
Lawrence  basin  is  slightly  less  than  half  its  rainfall,  while  on  the  Missis- 
sippi and  Ohio  the  discharge  is  about  a  fourth  of  the  rainfall.  If  the 
average  discharge  of  the  Laurentian  lakes  passed  through  a  river  one  mile 
wide  with  a  mean  velocity  of  one  mile  per  hour,  such  a  river  would  have 
a  depth  of  40  feet  from  shore  to  shore. 

The  volume  of  water  in  the  Laurentian  lakes  is  about  6,000  cubic 
miles,  of  which  Lake  Superior  contains  somewhat  less  than  one  half. 
Perhaps  a  better  idea  of  this  volume  may  be  obtained  when  it  is  said  that 
it  is  sufficient  to  sustain  Niagara  falls  in  their  present  condition  for  about 
100  years. 

The  mean  annual  rainfall  of  the  St.  Lawrence  basin  is  about  31 
inches  ;  and  the  mean  depth  of  Avater  evaporated  from  the  surfaces  of  the 
lakes,  between  20  and  30  indies. ^  llie  amount  of  precijutation  on  the 
water  surface  is,  therefore,  nearly  compensated  by  the  amount  evajiorated 
from  the  same  area. 


Chemistry  of  tlie  waters  of  the   St.  Tjawrence.  —  The   composition 
of  the  waters  of  the  Laurentian  lakes  is  shown  with  a})proximate  accuracv 

1  Thomas    Kusssell,     "Depth  of   Evaporation  in  the   United  States,"    ^lonthly   Weather 
Report,  U.  8.  Signal  Office,  Sept.  1888. 


60 


LAKES    OF    NORTH    AMERICA. 


by  an  analysis  of  the  water  of  St.  Lawrence  river  taken  near  Montreal. 
This  analysis  may  also  be  considered  as  representing  very  nearly  the  com- 
position of  the  material  carried  in  solution  by  the  lakes  and  rivers  of  the 
more  humid  portions  of  Xorth  America.^ 

Analysis  of  the  AVater  of  St.  Lawrexce  River. 
By  T.  Sterry  Hunt.'^ 


iNtiUEDLENTS. 

Pahts  rx  A  Thousand. 

Sodium,  Xa        

.00513 

.00115 

.03233 

^                    .00585 

.002i2 

.06836 

.00831 

trace 

.03700 

trace 

(( 

(( 

Potassium,  K 

Calcium,  Ca 

Magnesium,  Mg 

Chlorine,  CI 

Carbonic  acid,  CO, 

Sulphuric  acid,  SO. 

Phosphoric  acid,  HPO 

Silica,  SiOo 

Alumina,  ALO, 

Oxide  of  iron,  FeO 

Oxide  of  ^langanese,  MnO 

Total 

0.16055 

Taking  the  volume  of  the  St.  Lawrence  at  300,000  cubic  feet  per 
second,  the  computed  discharge  of  Lake  Ontario,  it  follows  from  the  above 
analysis  that  approximately  1.5  tons  of  mineral  matter  in  solution  is  trans- 
ported by  it  per  second,  or  about  50  million  tons  annually. 

Erosion  of  the  lake  shoi*es.  —  The  shores  of  the  Laurentian  lakes 
are  being  eroded  at  many  localities,  and  the  material  thus  removed  de- 
posited, in  part,  on  other  portions  of  the  coast  so  as  to  add  to  the  land 
area.  Some  information  in  this  connection  has  been  compiled  by  Charles 
Crosman,^  but  much  additional  data  is  required  before  general  conclusions 
of  value  can  be  reached. 

The  average  annual  recession  of  the  sea-cliff  along  the  west  side  of 
Lake  Michigan,  as  determined  by  Prof.  Edward  Andrews  from  a  some- 
what extended  series  of  ol)servations,  is  stated  to  be  about  5  feet ;  with  a 

1  Analyses  of  the  water  of  20  rivers  of  the  United  States  and  Canada  may  be  found  in 
Monograph  No.  XI,  U.  S.  Geological  Survey,  Table  A. 

2  Geological  Survey  of  Canada,  1863,  p.  .567. 

3  "  Chart  of  the  Great  Lakes."     Published  at  Milwaukee,  Wisconsin. 


RELATION    OF    LAKES    TO    CLIMATIC    CONDITIONS.  61 

maximum  at  certain  localities,  of  IG  feet.  In  the  neighborhood  of  Cleve- 
land, Ohio,  the  mean  recession  of  a  line  of  prominent  sea-cliffs  in  boulder 
clay,  for  a  period  of  40  years,  has  been  about  6  feet  per  annum. 

Observations  at  less  favorable  localities  show  a  similar  retreat  of 
other  portions  of  the  lake  shores,  but  definite  quantitative  observations 
have  seldom  been  recorded.  Enough  is  known  in  a  qualitative  way,  how- 
ever, to  show  that  important  changes  in  the  outlines  of  tliese  lakes  are  in 
progress.  The  waste  of  the  shore,  resulting  in  a  broadening  of  the  sur- 
faces of  the  lakes,  is  compensated  in  part  by  the  deposition  of  tlie  material 
removed  on  adjacent  area  so  as  to  extend  the  land  lakeward,  as,  for 
example,  at  the  south  end  of  Lake  ]\lichigan,  where  beaches  and  large 
sand  dunes  have  been  formed,  and  are  still  encroaching  on  the  lake. 
Observations  made  by  the  writer  at  various  localities  about  the  shores  of 
the  lakes,  together  with  the  reports  of  others,  show  conclusively  that  the 
process  of  broadening  the  lakes  by  the  erosion  of  their  shores  is  progress- 
ing more  rapidly  than  areas  are  being  reclaimed  by  dej)osition,  and  there- 
fore that  they  are  becoming  shallower. 

Commerce  and  fisheries.  —  The  importance  of  the  Laurentian  lakes 
as  highways  of  commerce  is  too  well  known  and  is  too  extended  a  subject 
to  receive  treatment  at  this  time,  even  if  it  fell  within  the  scope  of  the 
present  discussion.  Some  idea  of  the  magnitude  of  the  commerce  on 
these  inland  waters  may  be  had,  however,  from  the  reports  of  the  opera- 
tion of  the  Government  locks  at  Sault  St.  Marie,  which  show  that  11,557 
vessels  passed  through  them  during  the  year  ending  June  30,  1892,  car- 
rj'ing  over  10  million  tons  of  freight.  The  great  importance  of  the  com- 
merce of  the  Laurentian  lakes  will  be  better  appreciated,  by  those  who 
are  not  familiar  with  it,  when  it  is  compared  with  the  traffic  of  the  Suez 
Canal.  In  1889,  tlie  latest  date  at  which  comparative  data  are  at  hand, 
nearly  three  times  as  many  vessels  passed  through  the  locks  at  Sault  St. 
Marie  as  through  the  Suez  Canal,  although  the  latter  is  open  for  naviga- 
tion throughout  the  entire  year.  The  tonnage  during  the  same  year  was 
7,221,935  at  the  "Sou,"  as  against  6,783,189  for  the  Suez  Canal.  The 
importance  of  the  carrying  trade  of  the  Great  Lakes  is  also  shown  by  the 
fact  that  the  tonnage  of  vessels  constructed  on  them  each  year  for  several 
years,  has  been  about  equal  to  that  of  all  the  vessels  built  on  the  Atlantic, 
Pacific,  and  Gulf  coasts.  Still  more  striking  is  the  fact  that  the  amount 
of  goods  carried  each  year  on  these  inland  waters,  is  far  in  excess  of  the 
entire  clearances  of  all  the  seaports  of  the  United  States,  and  several  mil- 


62  LAKES  OF  NORTH  AMERICA. 

lion  tons  in  excess  of  the   combined  foreign  and  coastal  trade  of  London 
and  Liverpool. 

The  demand  for  still  better  facilities  for  inter-lake  comnninication  has 
led  to  the  construction  of  still  larger  canals  and  locks,  and  no^y  improve- 
ments are  nearly  completed  which  will  allow  vessels  drawing  21  feet  of 
water  to  pass  from  Buffalo  to  Duluth.  It  is  expected  that  when  this 
improvement  is  made  the  trade  between  Lake  Supeiior  and  the  more 
southern  lakes  will  be  doubled  in  a  few  years.  Far-reaching  plans  for 
connecting  this  important  commercial  industry  with  ocean  highAvays  are 
under  consideration,  and  must  find  consummation  in  the  near  future. 

The  fisheries  of  the  Laurentian  lakes  is  another  subject  of  great  prac- 
tical importance,  as  they  are  the  most  extensive  lake  fisheries  in  the 
world.  The  lakes  abound  in  trout,  whitefish,  and  other  food  fishes,  and 
their  shores  are  dotted  with  fishing  villages,  in  which  a  hardy  population, 
skilled  in  all  that  pertains  to  their  calling,  are  living  their  humble  but 
useful  lives,  and  gaining  an  experience  which  well  fits  them  for  naval 
service  should  their  aid  be  called  for.  The  importance  of  these  inland 
fisheries  has  received  tardy  recognition  in  comparison  with  the  similar 
industries  of  the  sea  border,  but  they  are  a  substantial  element  of  national 
wealth  and  claim  the  most  careful  attention  and  guidance  of  l)oth  state 
and  national  legislators.  The  reports  of  the  U.  S.  Fish  Commission  show 
that  over  ten  thousand  persons  are  engaged  in  this  industry  :  that  the 
capital  invested  is  in  excess  of  four  and  one-half  millions  of  dollars  ;  and 
that  a  hundred  million  pounds  of  fish  are  secured  each  year,  which  bring  to 
those  actually  engaged  in  the  work  more  than  two  and  one-half  millions 
of  dollars. 

It  may  be  noted  as  an  item  of  interest  in  connection  with  the  physical 
history  of  the  Laurentian  basin,  that  in  lakes  Superior  and  Michigan  crus- 
taceans and  fishes  have  been  found  that  are  believed  to  be  identical  with 
living  marine  forms.  These  are  thought  by  some  persons  to  indicate  that 
the  lakes  in  which  they  occur  were  formerly  in  open  communication  with 
the  ocean.  Considerable  evidence,  derived  from  a  study  of  the  former 
extent  of  the  lakes,  and  of  the  fossils  in  the  sediments  of  previous 
water-bodies  in  the  same  basins,  do  not  seem  to  confirm  this  conclusion, 
however,  and  further  study  of  the  habits  and  means  of  migration  of  the 
species  referred  to,  is  necessary  l)efore  their  presence  in  inland  waters  can 
be  satisfactorily  accounted  for. 

The  movements  of  the  AAaters  of  the  Laurentian  lakes  and  a  few  facts 
respecting  their  temperature   and   their  influence   on  the  climate  of  the 


RELATION    OF    LAKES    TO    CLIMATIC    CONDITIONS.  63 

adjacent  land  have  already  been  referred  to  in  preceding  chapters.  Scarceh^ 
more  than  a  beginning  of  their  physical  study  has  been  made,  however, 
and  it  is  to  be  lioped  that  they  may  soon  receive  the  attention  in  this 
direction  they  so  well  deserve. 

Mountain  lakos.  —  No  account  of  the  lakes  of  North  America  is  com- 
plete that  does  not  include  some  notice  of  the  thousands  of  basins  amid 
the  nort^iern  Appalachians,  and  in  the  Cordilleras,  in  whicli  the  most 
magnificent  scenery  of  this  continent  is  reflected.  These  lakes  are  of  all 
sizes,  from  mere  tarns  across  Avhich  one  might  spiing  with  tlie  aid  of  an 
alpenstock,  to  ])road  plains  of  blue,  many  square  miles  in  area,  and  worthv 
of  comparison  with  tlie  most  beautiful  mountain  lakes  of  other  lands.  Of 
this  attractive  class  of  lakes  special  attention  can  only  be  given  at  present 
to  two  examples  AA-hich  are  destined  to  be  widel}'  known  on  account  of 
their  man}-  charms.  I  refer  to  Lake  Tahoe,  embosomed  among  the  peaks 
of  the  Sierra  Nevada,  and  lying  partially  in  California  and  partially  in 
Nevada ;  and  to  a  lake  of  a  different  character  but  not  less  magnificent, 
situated  in  the  Cascade  mountains,  in  the  State  of  Wasliington,  and  known 
as  Lake  Chelan. 

Lake  Tahoe.  —  This  "  gem  of  the  Sierra  "  is  situated  at  an  elevation 
of  6200  feet  above  the  sea  and  is-  enclosed  in  all  directions  by  rugged, 
forest-covered  mountain  slopes  which  rise  from  two  to  over  four  thousand 
feet  above  its  surface.  Its  expanse  is  unbroken  b}^  islands  and  has  an 
area  of  between  192  to  195  square  miles.  Its  diameter  from  north  to 
south  is  21.6  miles  and  from  east  to  west  12  miles. 

On  looking  down  on  Lake  I'ahoe  from  the  surrounding  pine-covered 
heights,  one  beholds  a  vast  plain  of  the  most  wonderful  blue  that  can  be 
imagined.  Near  shore,  where  the  bottom  is  of  white  sand,  the  waters  have 
an  emerald  tint,  but  are  so  clear  that  objects  far  beneath  the  surface  may 
be  readil}^  distinguished.  Farther  lakeward,  the  tints  change  b}^  insensil)le 
gradation  until  the  water  is  a  deep  blue,  unrivaled  even  by  the  color  of  the 
ocean  in  its  deepest  and  most  remote  parts.  On  calm  summer  days,  the 
sky  with  its  drifting  cloud  banks  and  the  rugged  mountains  with  their 
bare  and  usually  snow-covered  summits,  are  mirrored  in  the  placid  waters 
with  such  wonderful  distinctness  and  such  accuracy  of  detail,  that  one  is 
at  a  loss  to  tell  where  the  real  ends  and  the  duplicate  begins.  While 
floating  on  the  lake  in  a  boat,  the  transparency  of  the  water  gives  the  sen- 
sation that  one  is  suspended  in  mid  air,  as  every  detail  on  the  bottom, 
fathoms  below,  is  clearly  discernible. 


V-^ 


64  LAKES    OF    NOltTH    AMERICA. 

In  experimenting  on  the  transparency  of  the  waters,  Professor  John 
LeConte  found  that  a  white  disc  9.5  inches  in  diameter,  when  fastened  to 
a  line  and  lowered  heneath  the  surface,  was  clearly  visible  at  a  depth  of 
108  feet.  It  is  to  be  rememl)ered  tliat  the  light  reaching  the  eye  in  such 
an  experiment  traverses  through  water  twice  the  distance  to  which  the 
disc  is  submerged,  or  in  the  experiment  referred  to,  216  feet.  The  only 
instance  in  tlys  country  in  which  A\aters  have  been  found  to  be  more 
transparent  is  in  the  great  limestone-water  springs  of  Florida. 

Soundings  made  in  Lake  Tahoe  by  LeConte,  as  already  stated,  gave  a 
maximum  deptli  of  1645  feet,  but  a  more  detailed  survey  may  possiljly 
discover  still  more  profound  depths.  Those  measurements  show  that  the 
lake,  with  the  exception  of  Crater  lake,  Oregon,  is  the  deepest  inland 
water-body  in  America  yet  sounded,  and  exceeds  the  depth  of  any  of  the 
lakes  of  Switzerland,  but  is  not  so  deep  as  lakes  Maggiore  and  Como  on 
the  south  side  of  the  Alps. 

The  temperature  observations  made  in  Lake  Tahoe  previously  referred 
to,  furnish  an  illustrati(jn  of  the  fact  that  deep  lakes,  even  when  situated 
at  a  hio-h  elevation  and  sul^jeet  to  low  winter  temperatures,  do  not  freeze. 
The  surface  waters  are  cooled  in  winter  and  descend,  while  warmer  waters 
from  below  rise  and  take  their  place,  thus  establishing  a  cijculation,  but 
the  body  of  water  is  so  great  that  its  entire  mass  never  becomes  cooled 
sufficiently  during  the  comparatively  short  winters  to  check  the  upward 
circulation  and  allow  ice  to  form.  At  the  greatest  depth  reached  the 
temperature  was  39.2°  F.,  which  is  the  temperature  of  fresh  water  at  its 
maximum  density;  and  from  more  extended  observation  in  other  lakes, 
the  water  is  believed  to  retain  this  temperature  throughout  the  year. 

Lake  Tahoe  is  situated  at  such  an  altitude  that  its  shores  are  bleak 
and  inhospitable  during  a  number  of  months  each  year.  For  this  reason 
it  is  proljaljle  that  it  will  never  be  selected  as  a  place  of  continued  resi- 
dence by  any  consideraljle  number  of  families,  but  during  the  summer, 
when  the  adjacent  valleys  are  parched  by  desert  heat,  the  air  in  the  lake- 
filled  valley  is  cool  and  bracing  ;  it  then  furnishes  a  charming  retreat  for^ 
the  dwellers  of  the  cities  of  the  Pacific  coast,  as  well  as  for  more  distant 
wanderers.  As  a  place  for  summer  rest  and  recreation  it  is  second  to 
none  of  the  popular  resorts  of  the  United  States  or  Canada. 

The  waters  of  Lake  Tahoe  overflow  through  the  Truckee  canon  and 
form  a  bright,  swift-flowing  stream,  which  finds  its  way  to  Pyramid  and 
Wimiemucca  lakes,  situated  2400  feet  lower,  in  the  desert  valleys  to  the 
north.     The  waters  when  starting  on  their  troubled  journey  are  as  pure 


RELATION    OF    LAKES    TO    CLIMATIC    CONDITIONS.  65 

and  limpid  as  the  melting  snows  of  mountain  valle3's  can  furnish.  Analy- 
ses show  that  they  contain  only  0.0750  part  per  thousand  of  mineral 
matter  in  solution,  l)ut  the  lakes  into  which  they  flow  and  of  which  the}^ 
form  almost  tlie  sole  supply,  are  alkaline  and  saline  owino-  to  lono- 
concentration.^  __ 

An  example  of  an  isolated  drainage  system  is  here  furnished,  embrac- 
ing the  cool  summits  of  lofty  mountains  where  the  moisture  of  the  atmos- 
phere is  condensed  ;  a  mountain  reservoir  where  the  waters  are  stored  ;  a 
swift,  clear  stream  formed  by  the  overflow  of  tlie  reservoir  ;  and  the  bitter 
lakes  where  the  stream  empties  and  from  which  there  is  no  escape  except 
by  evaporation.  Such  an  attractive  field  for  geographical  study  should 
not  be  long  neglected.  A  careful  investigation  of  the  various  problems 
here  assembled  in  narrow  bounds,  would  form  a  thesis  of  unusual  interest. 
Will  not  some  student  or  some  class  of  students  in  our  universities  tell 
the  world  what  the  mountains  and  streams  in  this  fascinating  region  are 
doing,  explain  how  the  present  conditions  came  into  existence,  and  jjoint 
out  the  results  towards  which  they  are  tending? 

Ijake  Cholan.  —  Our  second  example  of  mountain  lakes,  selected  from 
the  large  number  that  shimmer  in  the  sunlight  amid  the  highlands  of  the 
Far  West,  lies  hidden  in  the  embrace  of  the  eastward-reaching  spurs  of 
the  Cascade  mountains  in  the  State  of  Washington,  and  until  recently 
was  so  remote  fiom  the  paths  ordinarily  followed  by  man,  that  its  very 
name  Avill  sound  strange  to  many  of  my  readers. 

Where  Columbia  river  crosses,  the  arid  region  between  the  Rocky i 
mountains  and  the  Cascade  range,  making  a  vast  sweep  about  the  north- 
ern and  western  margins  of  an  ancient  lava  flood,  it  washes  the  bases  of 
the  mountains  tn  the  west  and  receives  the  tribute  of  a  number  of  lakes, 
fed  by  the  melting  snow  on  the  higher  portions  of  the  range.  One  of 
these  lakes,  named  in  honor  of  Chelan,  an  Indian  chief  of  considerable 
local  renown,  whose  village  stands  on  its  shore,  empties  into  the  Columbia 
through  a  deep  tortuous  gorge  of  recent  origin  and  sends  a  swift  stream 
of  clear,  greenish-tinted  water  about  two  miles'long,  to  join  the  great  river 
in  the  adjacent  canon.  The  lake  is  a  narrow,  river-lik^  sheet  of  water, 
with  gentle  windings,  extending  westward  ihnn  the  Columljia.  seventy 
miles  into  the  mountains,  and  is  bordered  on  either  hand  by  a  continuous 
series  of  rugged  peaks  that  rise  from  five  to  over  seven'  thousand  feet 
above  its  surface.  The  deep,  narrow,  trench-like  valley,  now  partially 
1  For  analyses  of  the  waters  of  these  lakes,  see  p.  72. 


66  LAKES    OF    NORTH    AMERICA. 

water-filled,  continues  beyond  the  head  of  the  lake  for  a  distance  of  at 
least  twenty-five  miles,  becoming  more  and  more  wild  and  rugged  as  it 
nears  the  heart  of  the  highlands.  The  total  length  of  this  remarkable 
valley  is  not  less  than  one  hundred  miles,  and  its  width  at  the  level  of  the 
lake  seldom  exceeds  four  miles. 

The  sounding  line  has  shown  that  Lake  Chelan  is  over  eleven  hundred 
feet  deep,  but  its  full  depth  remains  to  be  determined.  In  several  sound- 
ings made  by  the  writer  in  its  central  and  western  portions,  no  bottom 
was  reached  at  the  depth  indicated.  The  surface  of  the  lake  is  but  950 
feet  above  the  sea,  so  that  the  bottom  of  the  trough  is  below  sea  level. 

Where  the  clear  water  of  the  lake  washes  the  precipitous  walls  enclos- 
ing it  there  is  no  beach,  and  scarcely  a  trace  on  the  rocks  to  show  that  it 
has  altered  the  topograj^hy  of  the  shores.  The  present  conditions  were 
initiated  at  such  a  recent  date  that,  practically,  the  only  changes  they  have 
produced  are  at  the  eastern  end  of  the  lake,  where  it  emerges  from  the 
rocky  defile  of  the  mountains  and  for  a  short  space  expands  between  com- 
paratively low  shores  of  gravel  and  sand.  In  this  region  high  terraces 
mark  the  former  level  of  the  water  surface. 

How  the  great  gash  in  the  mountain,  fully  one  hundred  miles  long< 
and  now  filled  for  more  than  a  thousand  feet  in  depth  by  the  lake,  was 
formed,  is  not  easy  to  explain.  Previous  to  the  birth  of  the  present  lake 
the  valley  was  occupied  by  a  large  glacier  which  flowed  through  it  and 
joined  another  great  ice  stream  in  the  canon  of  the  Columbia.  The  ice 
smoothed  the  precipices  of  rock  and  piled  up  moraines  on  the  more  gentle 
slopes  at  the  east  end  of  the  valley,  but  that  the  main  depression  existed 
before  the  glacial  invasion  is  evident  and  is  in  harmony  with  the  histories 
of  many  other  valleys  in  the  Cordilleran  region.  The  valley  has  a  still 
more  ancient  history,  and  in  Tertiary,  or  in  part  perhaps  in  pre-Tertiary 
times,  was  excavated  in  the  hard  granite,  now  seen  in  its  enclosing  walls, 
by  the  slow  wear  of  streams.  It  is  a  stream-cut  channel,  but  where  the 
stream  rose  that  did  the  work,  or  whence  it  flowed,  remains  to  be  deter- 
mined by  a  careful  study  of  all  the  facts  bearing  on  the  problem. 
'X  It  has  been  the  writer's  fortune  to  pitch  his  camp  on  the  borders  of  both 
Lake  Tahoe  and  Lake  Chelan.  As  the  scenery  of  each  is  conjured  up  in 
rever}^,  it  is  difficult  to  decide  which  is  the  more  remarkable  or  which 
should  have  the  first  rank  among  the  mountain  lakes  of  America.  Each 
lake  is  surrounded  by  forest-covered  mountains  of  majestic  proportions 
and  rich  and  varied  details  ;  the  waters  of  each  lake  are  clear  and  deep  in. 
color,  or  varied  by  silvery  reflections  and  iridescent  tints  where  the  not 


EELATION    OF    LAKES    TO    CLIMATIC    CONDITIONS.  67 

too  gentle  mountain  Avinds  touch  their  surfaces  ;  in  each  instance  the 
scene  is  fresh  and  unmarred,  and  has  the  charm  of  remoteness  so  welcome 
to  many  who  are  weary  with  the  ways  of  men. 

At  Talioe  tlie  views  are  wide  and  far-reaching.  The  shaggy  moun- 
tains are  picturesquely  grouped  about  the  central  plain  of  waters  and  the 
scene  is  open  and,  for  a  mountain  stronghold,  mild  and  pleasing. 

At  Lake  Chelan  the  scenery  is  wild  and  rugged.  The  narrow  stream- 
like sheet  of  water,  with  gently  curving  shores,  extends  far  into  the 
mountains  and  cannot  be  comprehended  at  a  glance.  Each  view,  as  one 
ascends  the  lake,  gives  suggestions  of  something  still  more  grand  beyond. 
Each  turn  reveals  hidden  l)eauties  that  entice  one  on  and  on.  The 
bordering  mountains  become  more  and  more  rugged,  as  we  venture 
farther  into  their  embrace.  Each  newly  discovered  peak  is  higher  and 
more  imposing  than  its  predecessor  ;  until  at  the  head  of  the  lake,  the 
most  lofty  summits  of  the  range,  usually  white  with  snow,  can  be  seen  far 
up  the  gorge  beyond  where  boats  can  go.  The  narrow  valley  bottom 
beyond  the  lake  is  filled  with  majestic  trees  and  a  rich  [)rofusion  of  lower 
vegetation  of  almost  tropical  density ;  the  dark  vine-entangled  forest 
seems  striving  to  conceal  some  mysterious  shrine  farther  within  the 
heart  of  the  mountains.  A  clear,  swift  stream  flows  silently  beneath  the 
deep  shade  of  the  broad-leaved  sycamores;  and  from  far  within  the  hidden 
recesses  of  the  valley,  the  echoes  of  unseen  cataracts  come  faintly  to  the 
ear.  What  wonders  exist  in  the  upper  portion  of  the  valley  are  not 
known,  as  they  have  been  seen  by  only  a  few  white  men  and  have  never 
been  described. 

All  of  the  surroundings  of  this  wonderful  lake  are  so  fresh  and  speak 
so  strongly  of  the  untamed  beauties  of  Nature  in  her  wildest  moods,  that 
a  visit  to  the  regfion  has  the  zest  and  fascination  of  entering  an  undis- 
covered  country,  where  each  step  takes  one  farther  and  farther  into  the 
unknown. 

The  veofetation  of  the  Cascade  mountains  is  far  more  luxuriant  and 
varied  than  the  flora  of  the  Sierra  Nevada.  In  every  nook  and  corner  one 
is  surprised  and  charmed  with  the  rank  luxuriance  of  the  gracefully 
bending  ferns,  or  the  profusion  and  brilliancy  of  the  flowers.  On  the 
higher  slopes,  between  the  forests  and  tlie  bare  summits  of  the  cloud- 
capped  peaks,  the  angles  of  the  rock  are  ?ioftened  by  luxuriant  mosses  and 
liphens,  and  the  gray  of  the  cold  granite  is  brightened  by  Alpine  blossoms. 
''^  Tent  life  on  the  shore  of  either  Lake  Tahoe  or  Lake  Chelan  is  delight- 
ful.    Each  lake  has  its  own  peculiar  charms,  but  their  influences  on  the 


68  LAKES    OF    NORTH    AMERICA. 

mind  are  diiferent.  One  or  the  other  will  be  declared  the  more  attractive 
according  to  the  temperament  of  the  person  who  yields  himself  to  their 
influences.  Each  is  poetic,  and  will  weave  a  web  of  golden  fancies  in  the 
mind  of  its  admirer,  which  will  be  as  nectar  to  his  tlioughts  when  his  feet 
tread  other  and  less  inspiring  paths. 

Owing  to  the  ver}'  moderate  elevation  of  Lake  Chelan,  its  climate  is 
mild  throughout  almost  the  entire  year,  and  is  delightful  from  early  spring 
to  late  autumn.  Since  the  building  of  the  Great  Northern  railroad,  this 
charming  lake  of  the  Cascades  is  quite  accessible.  The  traveler  leaving 
the  railroad  at  Wenatchee,  may  ascend  the  Columbia  by  steamer,  to  Chelan 
Crossing,  a  distance  of  about  forty  miles,  and  thus  see  something  of  the 
great  river  of  the  Northwest,  From  Chelan  Crossing,  a  ride,  or  prefer- 
ably a  walk  of  two  miles,  will  bring  the  visitor  to  Chelan  "  City  "  as  a 
unique  group  of  several  hundred  "  claim  shanties  "  is  termed.  The  houses 
in  this  silent  city  were  built  simply  for  the  purpose  of  acquiring  some 
sort  of  a  title  to  the  land  on  which  they  stand  and  were  never  intended 
for  habitation.  The  generous  hospitality  of  the  sparse  population  in  this 
frontier  town  makes  up  for  their  lack  of  numbers.  Every  visitor  who 
comes  to  see  the  beauties  of  the  lake  and  mountains,  of  which  the  dwellers 
of  the  region  are  justly  proud,  will  be  welcomed. 

On  the  lake  there  are  small  steamers,  which  make  regular  trips  to  its 
head,  and  boats  for  sailing  and  fishing.  The  trout  in  the  lake  are  abun- 
dant and  unusually  fine.  Mountain  goats  inhabit  the  higher  mountains, 
and  afford  sport  equal  to  the  chamois  chase.  Small  hotels  have  been 
built  on  the  shores  of  the  lake  for  the  accommodation  of  summer  tourists, 
fishermen,  and  hunters.  I  mention  these  details  for  the  purpose  of  assur- 
ing the  reader  that  he  will  find  traveling  easy  and  agreeable,  if  he  wishes 
to  verify  what  has  been  stated  in  reference  to  the  attractions  of  one  of  the 
wildest  and  grandest  lakes  in  America. ^ 

Only  two  examples  of  the  mountain  lakes  of  America  have  been 
referred  to,  for  the  reason  tliat  the  space  at  command  does  not  permit  even 
the  mention  of  the  hundreds  of  charming  examples,  many  of  them  of 
greater  size  and  in  their  milder  fashion  as  attractive  as  those  of  the  Sierra 
Nevada  and  Cascade  mountains,  which  add  variet}'  and  beauty  to  the  New 
England  States,  New  York,  etc.     Extending  our  survey  to  Canada,  a  still 

1  A  more  complete  account  of  the  region  about  Lake  Chelan  than  can  be  given  at  this 
time,  may  be  found  in  a  report  on  the  Upper  Columbia  River  by  Lieut.  T.  W.  Symons  ;  47th 
Congress,  1st  session,  Senate  Executive  Doc.  No.  186,  Wa.shington,  1882  ;  and  in  a  report  by 
the  author,  on  a  Geological  Reconnoissance  in  Central  Washington,  U.  S.  Geol.  Surv., 
Bulletin  No.  108. 


RELATION    OF    LAKES    TO    CLIMATIC    CONDITIONS.  09 

greater  host  of  inland  water  bodies  of  almost  every  variety  imaginable, 
attract  the  attention  and  cause  our  pen  to  linger ;  but  here  again  we  can 
only  say  that  they  belong  to  a  great  class  of  which  types  have  been  biiefly 
described. 

Saline  Lakes. 

Saline  lakes  are  formed  principally  in  two  ways.  First,  by  the  isola- 
tion of  bodies  of  sea  water,  as  where  a  rise  of  the  land  cuts  off  an  arm 
of  the  ocean,  or  sand  bars  or  coral  reefs  enclose  lagoons.  Second,  by 
the  concentration  by  evaporation  of  ordinary  river  waters  in  enclosed 
basins.     The  first  are  of  oceanic  and  the  second  of  terrestrial  origin. 

Saline  lakes  of  oceanic  origrin.  —  There  are  no  conspicuous  exam- 
ples of  this  class  of  lakes  in  North  America,  although  lagoons  cut  off 
from  the  ocean  by  sand  bars  do  occur,  especially  along  the  southern 
Atlantic  coast. 

A  large  lake  of  salt  water  that  was  isolated  from  the  ocean  by  a  rise 
of  the  intervening  land  formerly  occupied  the  valley  of  Lake  Champlain, 
but  has  been  freshened  and  its  surface  lowered  by  overflow. 

Tlie  type  of  saline  lakes  wliich  were  formerly  arms  of  the  ocean  is 
furnished  by  the  Caspian  sea,  the  largest  body  of  inland  water  known. 
The  observations  of  many  travelers  have  shown  that  this  sea  has  been 
divided  from  the  ocean  by  the  elevation  of  the  intervening  land.  The 
climate  of  southwestern  Asia  is  arid,  and  over  large  areas  evaporation  is 
in  excess  of  precipitation.  For  this  reason  the  Caspian  has  contracted  its 
borders,  in  spite  of  the  large  contriljution  of  water  delivered  to  it  by  the 
Volga  and  other  streams. 

There  is  evidence  in  the  chemical  composition  of  the  waters  of  the 
Caspian,  and  in  the  topography  of  land  separating  it  from  the  Black  sea, 
to  indicate  that  at  first  it  was  freshened  by  overflow,  as  in  the  case  of 
the  ancient  lake  of  Champlain  valley,  and  that  its  present  salinity  has 
resulted  principally  from  the  concentration  of  river  waters.  It  may  be 
considered,  therefore,  of  oceanic  or  of  terrestrial  origin  as  one  chooses. 

The  Caspian  is  180,000  square  miles  in  area,  or  nearly  six  times  the 
size  of  Lake  Superior.  Its  maximum  depth  is  in  the  neighborhood  of 
3.000  feet,  and  exceeds  the  depth  of  any  other  lake  known.  It  is  with- 
out outlet.  Its  waters  contain  (3.294  parts  in  a  thousand  of  mineral 
matter  in  solution,  consisting  i)rincipally  of  sodium  chloride  and  mag- 
nesium sulphate.     The  waters  of  the  ocean,  it  will  be  remembered,  con- 


70  LAKES    OF    NORTH    A:MERICA. 

tain,  on  an  average,  34.4  parts  per  thousand,  or,  in  round  numbers,  3.5 
per  cent. 

One  of  the  most  instructive  features  connected  with  the  Caspian  is 
the  manner  in  which  it  h)ses  its  saline  constituents  by  discharging  into 
a  secondary  basin,  where  the  Avaters  are  still  more  highly  concentrated. 
On  its  eastern  shore  there  is  a  deep  bay  or  gulf  known  as  Karabogaza, 
which  is  nearly  shut  off  from  the  main  water-body  by  intervening  sand 
bars,  and  receives  its  only  influx  through  an  opening  in  the  bar  about 
140  yards  broad  and  5  feet  deep.  The  water  escapes  from  Karabogaza 
solely  by  evaj^oration,  and  is  replaced  by  a  current  from  the  Caspian 
which  has  been  estimated  by  Von  Baer  to  carry  350,000  tons  of  saline 
matter  daily  from  the  sea  to  the  gulf.  The  waters  of  the  gulf  have 
reached  the  point  of  saturation  for  common  salt,  and  precipitation  is  tak- 
ing place.  These  pecmiar  conditions  are  of  great  interest,  not  only  in 
showing  how^  deposits  of  salt  may  accumulate,  but  also  in  illustrating 
the  manner  in  which  an  enclosed  lake  may  deposit  a  large  part  of  its 
foreign  matter  without  the  entire  water-body  becoming  highly  concen- 
trated. 

Saline  lakes  of  teri'estrial  origin.  —  The  existence  of  lakes  of  this 
class  depends  upon  a  combination  of  topographic  and  climatic  conditions. 
The  basins  they  occupy  may  originate  in  almost  any  of  the  various  ways 
enumerated  in  Chapter  I.  As  a  rule  the  lakes  of  this  class  in  North 
America  occupy  depressions  formed  by  movements  in  the  earth's  crust 
which  have  cut  off  large  areas  from  free  drainage  to  the  sea.  Such  en- 
closed basins,  however,  can  only  continue  in  regions  where  the  rainfall 
is  small,  for  the  reason  that  if  precipitation  were  in  excess  of  evaporation, 
they  would  become  filled  to  overflowing.  The  most  favorable  conditions 
for  the  formation  of  inland  saline  lakes  are  found  where  high  mountains 
discharge  their  drainage  into  basins  where  the  climate  is  arid.  A  region 
of  condensation  of  atmospheric  vajDors  and  a  region  of  concentration  by 
evaporation  are  thus  supplied,  which  supplement  each  other. 

The  saline  lakes  of  arid  regions  are  peculiarly  sensitive  to  climatic 
changes,  and  undergo  many  fluctuations.  When  the  mean  annual  influx 
and  the  mean  annual  loss  by  evaporation  are  nearly  evenly  balanced,  lakes 
frequently  exist  only  during  the  rainy  season,  and  disappear  entirely  dur- 
ing the  hotter  portions  of  the  year,  leaving  broad,  smooth  mud  plains. 
Plains  of  this  character  are  a  characteristic  feature  of  the  arid  region  of 
North  America,  and  are  known  in  Mexico  and  in  the  southwestern  part 


Lakes  of  North  America. 


Plate  14. 


SALINE    AND    ALKALINE    LAKES    IN    THE    ARID    REGION. 


RELATION    OF    LAKES    TO    CLIMATIC    CONDITIONS.  71 

of  the  United  States  as  playas.  It  is  convenient  to  adopt  this  name, 
and  call  the  temporary  water-bodies  to  which  playas  owe  their  origin, 
play  a  lakes.  These  lakes  may  he  formed  by  a  single  shower  and  disap- 
pear in  a  few  hours,  or  they  may  endure  for  a  series  of  years  and  onl}'  be 
evaporated  to  dryness  during  seasons  of  exceptionally  low  rainfall  or  un- 
usually active  evaporation. 

When  enclosed  lakes  of  arid  regions  are  more  permanent,  they  fluctu- 
ate in  volume,  and  consequently  in  extent  and  in  density,  from  season  to 
season,  and  are  so  sensitive  to  climatic  changes  that  they  show  marked 
variations  when  ordinary  weather  observations,  taken  at  a  limited  number 
of  localities  in  their  neighborhood,  fail  to  indicate  analogous  changes  in 
atmospheric' conditions. 

The  terrestrial  saline  lakes  of  North  America  are  confined  to  the  arid 
region  of  Mexico  and  the  United  States,  although  small  pools  of  alkaline 
water  do  occur  on  the  great  plains  in  the  sul>humid  region  east  of  the 
Rocky  mountains  both  in  the  United  States  and  Canada.  The  saline 
lakes  of  the  United  States  are  confined  almost  entirely  to  Utah  and 
Nevada  and  adjacent  portions  of  the  Great  Basin.  The  distribution  of 
some  of  the  more  important  lakes  here  referred  to,  is  indicated  on  the 
accompanying  map  forming  Plate  14.  The  chemical  composition  of  their 
waters  is  shown  in  the  table  on  page  72. 

Chemical  precipitates.  —  The  deposition  of  mechanical  sediments,  as 
clay  and  sand,  in  lake  basins  has  already  been  referred  to.  This  takes 
place  in  all  lakes  without  Sf)ecial  reference  to  their  chemical  composition. 
When  lake  waters  become  concentrated  by  evaporation,  however,  the 
material  contributed  to  them  in  solution  may  be  precipitated,  and 
either  mingle  with  the  mechanical  sediments  or  form  deposits  of 
purely  chemical  origin.  Chemical  precipitates,  like  mechanical  sedi- 
ments, may  furnish  evidence  of  important  changes  in  a  lake's  history, 
and  are  also  frequently  of  great  interest  on  account  of  their  commercial 
value. 

As  already  seen,  enclosed  lakes  are  constantly  receiving  contributions 
from  streams,  springs,  and  rain,  but  do  not  overfloAV,  the  influx  l)eiiig 
counterbalanced  by  evaporation.  This  assures  us  that  in  the  earlier  stages 
of  their  history,  at  least,  the  amount  of  saline  matter  held  in  solution  must 
increase  from  year  to  year  and  from  century  to  centuiy.  This  process 
continuing,  a  time  is  eventually  reached  when  the  waters  will  be  saturated 
with  one  or  more  of  its  saline  constituents  and  precipitation  begin.    Waters 


/:: 


LAKES    OF    NORTH    AMERICA. 


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EELATION    OF    LAKES    TO    CLIMATIC    CONUITIOXS.  73 

holdiiio-  a  number  of  salts  in  solution,  when  slowly  evaporated,  do  not 
deposit  them  in  a  homogeneous  mass,  but  in  successive  layers  of  varying 
composition.  As  the  order  in  which  different  salts  are  deposited  varies 
with  the  composition  of  the  waters,  it  is  safe  to  say  that  in  no  two  lakes 
is  the  succession  of  saline  deposits  formed  on  evaporation  apt  to  be  the 
same.  Disregarding  for  the  present  the  reaction  of  the  various  salts  upon 
each  other,  it  is  evident  that  in  the  evaporation  of  natural  waters  the 
order  in  which  the  contained  salts  will  be  precipitated  is  inversely  as  the 
order  of  their  solubility.  For  example,  a  salt  which  rec^uires  a  large 
amount  of  water  for  its  solution,  or,  in  other  words,  is  sparingly  soluble, 
will  reach  its  point  of  saturation  and  commence  to  crystallize  out  as 
evaporation  progresses,  previous  to  the  deposition  of  a  more  soluble  salt. 
To  illustrate  :  it  has  been  found  that  calcium  carbonate  requires  about 
10,000  times  its  weight  of  water,  saturated  with  carbon  dioxide,  for  its 
solution ;  while  calcium  chloride  is  deliquescent,  and  dissolves  in  about 
its  own  weight  of  water.  In  an  enclosed  lake  to  which  streams  and 
springs  are  bringing  these  two  salts  in  equal  quantities,  and  in  wliich 
evaporation  equals  or  exceeds  the  supply  of  fresh  water,  it  is  evident  tliat 
the  calcium  carbonate  would  reach  its  point  of  saturation  and  commence 
to  separate  long  before  the  waters  had  become  rich  in  calcium  chloride. 
In  fact,  owing  to  the  deliquescent  nature  of  the  chloride,  natural  evapora- 
tion seldom  proceeds  far  enough  to  cause  its  precipitation.  The  eai-ly 
deposition  of  calcium  carbonate,  when  natural  waters  are  concentrated  by 
evaporation,  is  rendered  the  more  certain  for  the  reason  that  it  is  by  far 
the  most  abundant  salt  found  in  surface  waters. 

The  fact  that  various  salts  are  deposited  in  a  regular  succession  when 
mineral  waters  are  evaporated,  is  of  great  service  in  separating  certain 
ones  in  a  pure  state  by  the  method  known  as  fractional  crystallization. 
In  evaporating  the  Ijrines  of  Syracuse,  New  York,  the  precipitation  .)f 
ferric  oxide  and  of  calcium  sulphate,  or  gypsum,  is  lirst  secured  by  mod- 
erate concentration  ;  the  brine  is  then  conducted  to  lower  vats  and  evapo- 
ration continued  until  the  sodium  chloride,  or  common  salt,  has  mostly 
crystallized  and  fallen  to  the  bottom  ;  the  mother-liquor,  rich  in  magnesium 
and  calcium,  is  then  allowed  to  go  to  waste.  A  similar  process  frequently 
takes  place  in  nature,  but  the  salts  precipitated  c(^llect  in  the  same  basin 
in  alternating  layers. 

In  the  Soda  lakes  near  Ragtown,  Nevada,  a  douljle  carbonate  of  sodium 
and  calcium,  known  as  the  mineral  gaylussite,  forms  on  the  bottom,  owing 
to  natural  concentration.     When  the  waters  are  still  farther  evaporated, 


74  LAKES    OF    NORTH    AMERICA. 

sodium  sulphate  and  sodium  carbonate  are  precipitated  previous  to  the 
crystallization  of  common  salt. 

It  has  been  found  on  concentrating  sea-water  that  calcium  carbonate 
is  usually  the  first  constituent  to  be  precipitated.  This  salt  is  not  always 
found  when  the  waters  of  the  ocean  are  analyzed,  but  may  usually  be 
detected  in  samples  taken  near  shore.  The  vast  quantity  delivered  to 
the  ocean  by  rivers  is  soon  eliminated  by  plants  and  animals  and  secreted 
in  their  tissues. 

The  succession  of  chemical  precipitates  formed  in  sea-water  has  been 
described  by  M.  Dieulafait  ^  as  follows  : 

"  First  a  very  weak  precipitation  occurs  of  carbonate  of  lime  (calcium 
carbonate),  with  a  trace  of  strontium,  and  of  hydrated  sesquioxide  of  iron, 
minfrled  with  a  slight  proportion  of  manganese.  The  water  then  con- 
tinues to  evaporate,  but  remains  perfectly  limpid,  without  forming  any 
other  deposit  than  the  one  I  have  mentioned,  till  it  has  lost  80  per  cent 
of  its  original  volume.  It  then  begins  to  leave  an  abundant  precipitate  of 
perfectly  crystallized  sulphate  of  lime  with  two  equivalents  of  water  or 
gypsum,  identical  in  geometrical  form  and  chemical  composition  with 
that  of  the  gy})sum-beds.  This  deposit  continues  until  the  water  has 
lost  8  per  cent  more  of  its  original  volume  ;  then  all  precipitation  ceases 
till  2  per  cent  more  of  the  original  quantity  of  water  has  evaporated 
away.  Then  a  new  deposit  begins,  not  of  gypsum,  but  of  chloride  of 
sodium,  or  sea  salt.  .  .  .  The  deposition  of  pure  or  commercial  salt  con- 
tinues till  the  volume  of  the  water  has  been  again  reduced  by  one-half, 
when  a  precipitation  of  sulphate  of  magnesium  begins  to  take  place  with 
it.  This  continues,  the  two  salts  being  deposited  in  equal  quantities,  till 
only  3  per  cent  of  the  original  quantity  of  water  is  left.  Finally,  when 
the  water  has  been  concentrated  to  2  per  cent,  carnallite,  or  the  double 
chloride  of  potassium  and  magnesium,  is  dej^osited.  Spontaneous  evapo- 
ration cannot  go  much  further.  The  residual  mother-water  will  not  dry 
up  at  the  ordinary  temperature,  even  in  the  hottest  regions  of  the  globe  ; 
its  chief  constituent  is  chloride  of  magnesium.  A  body  of  sea-water 
evaporated  naturally  will,  then,  leave  a  series  of  deposits  in  which  we 
will  find,  as  we  dig  down,  the  following  minerals  in  order :  deliquescent 
salts,  including^. chiefly  chloride  of  magnesium  ;  carnallite,  or  double  chlo- 
ride of  potassium  and  magnesium ;  mixed  salts,  including  chloride  of 
sodium  and  sulphate  of  magnesia ;  sea-salt,  mixed  with  sulphate  of  mag- 
nesia; pure  sea-salt;  pure  gypsum;  weak  de[)Osits  of  carbonate  of  lime 
with  sesquioxide  of  iron,  etc." 

1  Popular  Science  Monthly,  October,  1892. 


RELATION    OF    LAKES    TO    CLIMATIC    CONDITIONS.  75 

In  the  natural  evaporation  of  water  in  enclosed  basins  the  succession 
will  seldom  be  as  regular  as  described  above,  for  the  reason  that  the  process 
is  apt  to  be  interrupted  by  the  addition  of  fresh  supplies  of  water,  and  the 
succession  begun  anew,  or  else  chemical  changes  initiated  which  will  vary 
the  results.  In  this  connection  it  is  to  be  noted  also  that  changes  of  tem- 
perature, as  from  summer  to  winter,  may  modify  the  succession  of  salts 
dej^osited. 

The  separation  of  sodium  sulphate,  potassium  chloride,  and  common 
salt  from  the  mother  liquor  derived  from  the  concentration  of  sea-water, 
by  alternate  evaporation  and  cooling,  is  the  principle  of  Balard's  well- 
known  process  largely  used  for  obtaining  salt  from  sea-water  in  the  south 
of  Europe.  In  Mesel's  modification  of  this  process,  a  low  temperature  is 
obtained  artificially.  When  sea-water  is  concentrated  until  its  specific 
gravity  is  1.24  (28°  of  Beaume's  hydrometer)  it  deposits  about  four-fifths 
of  the  common  salt  it  originally  contained  ;  after  adding  10  per  cent  of 
sea-water  to  the  mother  liquor  remaining,  it  is  passed  througli  a  refriger- 
ating machine  and  its  temperature  Towered  to  — 18°  C.  The  low  tempera- 
ture causes  double  decomposition  to  take  place  between  the  magnesium 
sulphate  and  the  sodium  chloride,  sodium  sulphate  being  deposited  and 
the  magnesium  chloride  remaining  in  solution. ^ 

A  process  similar  to  that  just  described  occurs  in  nature,  as  is  shown 
by  the  precipitation  of  large  quantities  of  sodium  sulphate  from  the  waters 
of  Great  Salt  lake,  during  cold  weather.  This  anticipation  of  Balard's 
process  is  noticed  in  advance  in  connection  with  other  features  of  Great 
Salt  lake. 

The  correspondence  betAveen  the  succession  of  salts  formed  by  the 
evaporation  of  sea-water,  and  the  succession  found  in  many  saline  deposits 
deeply  buried  in  the  earth's  crust,  is  of  great  interest  and  no  doubt 
explains  the  genesis  of  some  natural  accumulations  of  this  character.  It 
is  not  always  necessary,  however,  in  seeking  an  explana'tion  of  the  origin 
of  beds  of  common  salt,  gypsum,  etc.,  found  in  lenticular  masses  among 
stratified  rocks,  to  assume  that  they  were  precipitated  from  isolated  bodies 
of  sea-Avater.  On  the  contrary,  the  study  of  saline  lakes  has  shown  that 
simflar  deposits  may  result  from  the  long  concentration  of  ordinary 
river  waters.  So  far  as  we  are  at  present  concerned,  however,  the 
process  in  either  case  is  the  same,  since  the  waters  of  the  ocean  itself 
owe  their  salinity  in  a  great  degree  to  the  concentration  of  the  waters 
of  streams. 

1  Report  of  Juries  :  International  Exliibition,  1862,  Class  II,  pp.  48-54. 


76  LAKES    OF    NORTH    AMERICA. 

Knowing  the  snccession  in  ^^•llicll  varions  salts  are  eliminated  when 
waters  are  concentrated  by  evaporation,  it  becomes  possible  to  determine 
in  some  instances,  from  the  succession  of  salts  discovered  in  a  desiccated 
lake  Ijasin,  what  changes  occurred  in  the  life  of  the  lake  from  which  they 
were  precipitated.  In  the  case  of  Lake  Lahontan,  descril)ed  in  advance, 
this  method  has  led  to  interesting  conclusions.  In  a  similar  way,  the 
cliemical  composition  of  a  lake  enables  one  to  draw  important  inferences 
in  reference  to  its  .past  history.  A  lake  in  which  the  rarer  elements  found 
in  tributary  streams  are  abundant,  must  have  undergone  a  long  period  of 
concentration,  and  formed  deposits  of  the  more  common  and  less  readily 
soluble  salts.  If  a  lake  occupying  an  inclosed  basin  which  has  never 
overflow^l,  contains  but  a  small  percentage  of  the  salts  most  common  in 
the  inflowing  streams,  it  is  evident  that  there  must  be  some  process  by 
which  such  salts  may  be  eliminated  without  being  flooded  out.  Search 
should  then  be  made  for  this  new  principle. 

When  lake  waters  are  concentrated  the  first  precipitates  formed,  as 
already  seen,  are  ferric  oxide  and  calcium  carbonate.  These  substances  are 
retained  in  solution  mainly  by  reason  of  the  presence  of  carbon  disxide, 
carbonic  acid,  in  the  water.  As  evaporation  progresses  and  also  when  the 
waters  are  agitated,  as  in  the  breaking  of  waves  on  shore,  the  carbon 
dioxide  escapes  and  the  iron  and  lime  previously  held  in  solution  are 
precipitated.  The  iron  while  in  solution  is  in  chemical  combination  with 
the  carbon  dioxide,  forming  ferric  carbonate,  when  it  loses  its  carbonic 
acid  it  is  precipitated  as  ferric  oxide.  The  lime  in  solution  is  beli^ed 
to  be  in  the  form  of  the  bicarbonate,  and  on  losing  carbon  dioxide  is  pre- 
cipitated as  the  carbonate. 

It  is  a  fact  of  geological  interest  that  iron  and  lime  held  in  solution 
may  also  be  precipitated  on  account  of  the  withdrawal  of  carbon  dioxide 
through  the  agency  of  plant  life.  Low  forms  of  vegetation,  knoAvnas 
algae,  thrive  in  the  waters  of  both  fresh  and  saline  lakes  and  even  in  hot 
springs  where  the  temperature  approximates  to  that  of  boiling  Avater. 
Through  the  vital  action  of  this  vegetation  carbon  dioxide  is  removed 
from  water  in  much  the  same  manner  that  higher  forms  of  ])lant  life 
eliminate  it  from  the  atmosphere.  Carbon  is  assimilated  and  oxygen 
liberated.  Iron  on  parting  with  its  carbon  dioxide  unites  with  the  liber- 
ated oxygen  and  is  precipitated  as  ferric  oxide. 

It  has  recently  been  shown  that  large  deposits  of  Ijoth  calcareous  tufa 
and  silicious  sinter  are  deposited  through  the  agency  of  fresh  water  algae 
from  the  waters  of  hot  springs  in  the  Yellowstone  Park.     The  silicia 


RELATION    OF    LAKES    TO    CLIMATIC    CONDITIONS.  77 

in  such  instances  seems  to  be  secreted  by  the  phints  as  a  part  of  their 
vital  function,  but  the  process  is  not  well  understood.^ 

The  origin  of  oolitic  sand,  'consisting  of  little  spheres  formed  of 
concentric  coats  of  calcium  carbonate,  along  the  shores  of  Great  Salt  lake, 
has  been  referred  to  an  analogous  process.^ 

Coral-like  growths  of  calcareous  tufa  in  some  of  the  strongly  alkaline 
lakes  of  the  Great  Basin  are  also  thought  to  owe  their  origin  to  the 
agency  of  low  forms  of  plant  life.^ 

An  important  feature  in  this  function  of  sub-aqueous  plants,  is  that 
calcium  carbonate  may  be  precipitated  from  waters  that  are  far  below  the 
point  of  saturation.  In  some  instances  precipitation  is  known  to  occur  in 
this  manner  from  water  in  which  chemical  tests  fail  to  reveal  more  than  a 
trace  of  calcium. 

Ferric  oxide  is  not  known  to  be  an  important  deposit  in  any  of  the 
lakes  of  North  America,  although  found  in  abundance  in  many  swamps. 
In  Sweden,  however,  its  precipitation  from  the  water  of  fresh  lakes  is  so 
abundant  that  it  is  of  commercial  value.  The  iron  is  carried  into  the 
lake^  by  streams,  as  a  carbonate,  and  is  precipitated  on  account  of  the  loss 
of  carbon  dioxide,  in  part  at  least,  through  the  agency  of  low  forms  tif 
vegetative  life.  In  some  instances  diatoms  are  thought  to  play  an  im- 
portant part  in  secreting  the  iron. 

With  this  brief  sketch  of  the  manner  in  which  precipitates  may  be 
formed  in  lakes,  let  us  turn  to  actual  cases  where  the  process  is  in 
op«?fation.  Of  the  considerable  number  of  saline  lakes  of  North  America 
that  have  been  studied,  two  are  here  selected  as  types.  These  are  Great 
Salt  lake,  Utah,  and  ]\Iono  lake,  California. 

Great  Salt  lake,  Utah.  —  This  celebrated  sea  is  situated  in  the  eastern 
portion  of  the  Great  Basin  near  the  west  base  of  the  Wasatch  mountains. 
Its  hydrographic  basin  has  an  area  of  54.|000  square  miles,  and  is  divided 
into  two  strongly  contrasted  portions.  The  eastern  part  is  mountainous 
and_contains  peaks  12,000  feet  in  height  above  the  sea,,  ot  8000  feet-aWve 
the  lake..  The  western  portion  is  composed  of  desert  valleys  but  little 
elevated  above  the  lake  surface,  and  separated  l)y  narrow,  abrupt,  desert 
ranges  rising  from  one  to  two  thousand  feet  or  more  above  adjacent  valleys. 

1  W.  H.  Weed.  "  The  Formation  of  Travertine  and  Silicious  Sinter  by  the  Vegetation 
of  Hot  Springs,"  9th  Annual  Keixirt,  U.  S.  Geological  Survey,  1887-88,  pp.  613-670. 

2  A.  Rothplitz.    "On  the  Fornmtion  of  OiJlite,"  American  Geologist,  vol.  10,  pp.  270-282. 
,3  I.  C.  Russell.     "A  Reconnoissauce  in  Central  Washington,"  Bulletin  No.  108,  U.  S. 

Geological  Survey,  pp.  94-95. 


/O  LAKES    OF    NORTH    AMERICA. 

The  elevation  of  the  lake's  surface  varies  somewhat  during  different 
years  and  from  season  to  season,  owing  to  climatic  changes,  and  to  the 
fact  that  the  flow  of  the  streams  supplying  it  is  interfered  with  for  pur- 
poses of  irrigation.  Siiryeys_jQiade-  May  16,  1883,  gave  a  surface  level  of 
4218  feet  above  the  sea. 

Its  area  is  also  changeable.  On  a  map  made  from  surveys  under  the 
direction  of  Lieut.  Stansbury,  in  1850,  it  is  represented  as  having  an  area 
of  about  1750  square  miles.  A  second  map,  made  in  connection  with  the 
Fortieth  Parallel  survey,  in  charge  of  Clarence  King,  in  1869,  shows  an 
area  of  2X10  square  miles  ;  the  increase  in  19  years  being  420  square 
miles,  or  24  per  cent.  Its  outlines  when  these  surveys  were  made  are 
shown  in  Plate  15. 

At  its  highest  observed  stage  in  1869,  it  had  a  maximum  depth  of  49 
feet,  and  an  average  depth  of  approximately  19  feet.  In  1850,  the  maxi- 
mum depth  was  36  feet,  and  the  average  about  13  feet.  Since  1875, 
careful  records  of  the  fluctuations  of  level  have  been  made  and  ])oth 
annual  and  secular  changes  noted. ^  The  annual  high-water  stage  occurs 
in  June,  and  is  due  to  the  melting  of  the  snow  on  the  Wasatch  and 
Uintah  mountains.  The  fluctuations  embracing  a  series  of  years  have 
not  been  found  to  be  regular  in  their  periods  and  are  not  coincident  with 
observed  climatic  changes. 

The  shores  of  Great  Salt  lake  are  low  except  where  a  mountain  uplift 
projects  into  it  from  the  north,  forming  a  rocky  promontory,  and  for  a 
short  distance  on  its  south  shore  where  it  touches  the  northern  end  of  the 
Oquirrh  mountains.  Its  surface  is  broken  by  several  islands,  of  which 
two  are  short  mountain  ranges  of  the  type  so  characteristic  of  the  Great 
Basin.  These  rise  more  than  a  thousand  feet  above  its  surface  and  are 
rugged  and  precipitous.  They  stand  like  Nilometers  in  the  saline  waters, 
and  on  their  sides  are  many  horizontal  lines  marking  former  levels  of  the 
lake's  surface.  The  hig-hest  of  these  scorings  is  about  1000  feet  above 
the  present  water  surface. 

The  scenery  about  this  great  lake  of  the  Mormon  land  and  in  the  encir- 
cling mountains  is  unusually  fine,  in  spite  of  the  aridity  and  the  generally 
scant  vegetation  of  the  region.  The  sensation  of  great  breadth  that  the 
lake  inspires,  together  with  the  picturesque  islands  diversifying  its  sur- 
face, and  the  utter  desolation  of  its  shores,  give  it  a  hold  on  the  fancy,  and 
wakens  one's  sense  of  the  artistically  beautiful  in  a  way  that  is  unrivaled 

1  The  records  of  these  changes  up  to  1890,  together  with  a  discussion  of  their  significance, 
is  given  by  G.  K.  Gilbert,  in  Monograph  Xo.  1,  U.  S.  Geological  Survey. 


Lakes  of  Xortit  America. 


Plate  15. 


GREAT    SALT    LAKE,    UTAH.    (AFTER   GILBERT.) 


RELATION    OF    LAKES    TO    CLIMATIC    CONDITIONS.  79 

by  any  other  lake  of  the  Arid  region.  The  iiimsually  clear  air  of  Utah, 
especially  after  the  winter  rains,  renders  distant  mountains  remarkably 
sharp  and  distinct,  particularly  Avhen  the  sun  is  low  in  the  sky  and  a 
strong  sidelight  brings  the  sharp  serrate  crests  into  bold  relief  and  reveals 
a  richness  of  sculpturing  that  was  before  unseen.  At  such  time  the  colors 
on  the  broad  deserts,  and  amid  the  purple  hills  and  mountains,  are  more 
wonderful  than  artists  have  ever  painted,  and  exceed  anything  of  the 
kind  witnessed  by  the  dweller  of  regions  where  the  atmosphere  is  moist 
and  the  native  tints  of  the  rock  concealed  by  vegetation.  The  liills 
of  NcAV  England  when  arrayed  in  all  the  gorgeous  panoply  of  autumnal 
foliage  are  not  more  striking  than  the  desert  ranges  of  Utah  when 
ablaze  with  the  reflected  glories  of  the  sunset  sky.  The  rich,  native 
colors  of  the  naked  rocks  are  then  kindled  into  glowing  fires,  and  each 
cailon  and  rocky  gorge  is  filled  with  liquid  purple,  beside  which  even  the 
Imperial  dyes  would  be  dull  and  lusterless.  At  such  times  the  glories  of 
the  hills  are  mirrored  in  the  dense  water  of  the  lake  ;  their  duplicate 
forms  appearing  in  sharp  relief  on  the  paler  tints  of  the  reflected  sky. 
As  the  sun  sinks  behind  the  far-off  mountains,  range  after  range  fades 
through  innumerable  shades  of  purple  and  violet  until  only  their  highest 
battlements  catch  the  fading  glory.  The  lingering  twilight  brings  softer 
and  more  mysterious  beauties.  Ranges  and  peaks  that  were  concealed  by 
the  glare  of  the  noon-day  sun,  start  into  life.  Forms  tliat  were  before 
unnoticed,  people  the  distant  plain,  like  a  shadowy  encampment.  At  last 
each  remote  mountain  crest  appears  as  a  delicate  silhouette,  in  which  all 
details  are  lost,  drawn  in  the  softest  of  violet  tints  on  the  fading  yellow 
of  the  sky. 

To  one  who  only  beholds  the  desert  land  liordering  Great  Salt  lake  in 
the  full  glare  of  the  unclouded  summer  sun,  when  the  peculiar  desert 
haze  shrouds  the  landscape  and  the  strange  mirage  distorts  the  outline  of 
the  hills,  the  scenery  will  no  doubt  be  uninteresting  and  perha^DS  even 
repellent.  But  let  liim  wait  until  the  cool  breath  from  the  mountains 
steals  out  on  the  plain  and  the  light  becomes  less  intense,  and  a  transfor- 
mation will  be  witnessed  that  will  fill  his  heart  with  wonder. 

The  saline  and  alkaline  shores  of  Great  Salt  lake  are  either  naked 
mud  plains,  frequently  white  with  drifting  salts,  or  scantily  clothed  ^^•ith 
desert  shrubs.  The  absence  of  cons|)icuous  flowers  is  frequently  relieved 
by  broad  areas  covered  with  a  peculiar  plant,  known  as  Salicornia,  which 
flourishes  by  the  side  of  this  Dead  Sea  of  the  West,  where  all  other  vege- 
tation perishes.      The  Salicornia  grows   in  fleshy  stems,  without  leaves. 


80  LAKES    OF    NORTH    AMERICA. 

and  looks  not  unlike  branching  coral.  It  is  of  many  shades  of  red,  pink, 
and  yellow,  thus  still  further  increasing  its  resemblance  to  groves  of  living 
coral.  The  white,  alkaline  desert  is  frequently  tinted  by  this  strange 
lAunt  until  it  glows  like  a  field  of  Alpine  flowers.  There  are  many  other 
interesting  features  to  be  noted  by  the  visitor  to  the  great  desert-lake  of 
Utah,  but  its  physical  and  chemical  history  claims  our  attention  at  this 
time  rather  than  its  artistic  setting. 

The  streams  flowing  to  the  lake  rise  in  the  high  mountains  to  the  east 
and  are  clear  and  limpid,  and  of  such  purity  that  only  chemical  tests 
reveal  the  presence  of  the  mineral  matter  they  have  dissolved  from  the 
rocks  and  soils.  Several  of  these  streams  are  truly  rivers  in  volume,  as 
well  as  in  name,  and  send  a  never-ceasing  flood  to  the  lake.  Their  com- 
bined volumes  average  throughout  the  year  about  10,000  cubic  feet  per 
second.^ 

There  are  a  number  of  fissure  springs  about  the  lake,  or  rising  beneath 
its  surface.  In  some  instances  these  are  hot  and  contain  more  saline 
matter  in  solution  than  is  usually  found  in  surface  streams.  These  con- 
tribute a  considerable  quantity  of  the  saline  matter  found  in  the  waters  of 
the  lake,  but  it  is  believed  that  the  amount  thus  derived  is  less  than  that 
furnished  by  streams  from  the  mountains.  This  conclusion  rests  on 
incomplete  data,  however,  as  neither  the  volume  nor  the  composition  of  all 
the  springs  is  known.  None  of  the  springs  supplying  the  lake,  with  a 
single  known  exception,  of  small  volumes,  are  markedly  saline.  The  salts 
they  contain  are  acquired  largely  during  the  upward  passage  of  the  water 
through  the  sediment  of  former  lakes  and  their  influence  on  the  chemistry 
of  the  present  lake  is  more  important  than  in  the  case  of  any  other  lake  in 
the  same  region.  It  is  safe  to  conclude,  however,  that  the  combined 
volumes  of  the  streams  and  springs  now  tributary  to  the  lake,  if  not  con- 
centrated by  evaporation,  would  form  a  water  body  in  which  no  trace  of 
saline  matter  would  be  apparent  to  the  taste. 

Analyses  of  the  waters  of  Bear  river,  of  Utah  lake,  from  which  the 
Jordan  flows,  and  of  City  creek,  one  of  the  numerous  streams  from 
the  west  slope  of  the  Wasatch  mountains,  give  an  average  of  about 
0.2446  part  per  thousand  of  mineral  matter  in  solution.  This  may  be 
taken  as  the  average  composition  of  the  surface  stream  flowing  to  the 
lake.  As  will  be  noticed  on  referring  to  the  average  composition  of 
normal  rivers  previously  given,  the  mineral  matter  in  these  streams  is 
nearly  double  the  amount  carried  in  the  same  volume  of  water  by  streams 

1  G.  K.  Gilbert.     "Lands  of  the  Arid  Region,"  Washington,  1879,  p.  72. 


RELATION    OF    LAKES    TO    CLIMATIC    CONDITIONS. 


81 


in  more  humid  regions.     This  is  due,  in  a  measure,  to  the  active  evapora- 
tion that  takes  place  from  them  and  from  the  lakes  on  their  courses. 

The  waters  of  Great  Salt  lake  have  been  analyzed  at  six  different 
times.  The  results  of  these  several  analyses  are  widely  at  variance  on 
account  of  fluctuations  in  the  volume  of  the  lake.  Tlie  dates  at  which  the 
various  samples  analyzed  were  collected  and  the  total  solids  found  in  1000 
parts  of  water  are  here  given  :  ^ 

Date      .     .     .     1850    summer  1869     Aug.  1873     Dec.  1885     Aug.  1889     Aug.  1892  2 
Specific  gravity  1.170  1.111  1.102  1.122  1.1.57  1.156 


Parts  in  1000      224.2 


148.2 


136.7 


167.2 


195.5 


205.1 


Since  the  accompanying  table  of  analysis  of  lake  waters  was  compiled, 
my  attention  lias  been  directed  to  the  analysis  given  below,  which  in 
several  Avays  is  the  most  complete  and  satisfactory  that  has  been  pub- 
lished. 


Analysis  of  a  sample  of  the  Water  of  Great  Salt  Lake.     Collected 

August  9,  1892.2 

By  E.  Waller. 
[Expressed  in  Grams  in  a  Liter.    Specific  Gravity,  1.156.] 


Elements  and  Radicals. 

Probable  Combination. 

Na    .     .     . 75.825 

K                                                            3  9 '^5 

NaCl 192.860 

K._,SO^ 8.756 

LigvSO^ 0.166 

MgCla 15.044 

MgSO^ 5.216 

CaSO, 8.240 

Fe/jg  and  Al.Og 0.004 

Si()„ 0.018 

Surplus  SO3 O.Ool 

Li 0.021 

Mg 4.844 

Ca 2.424 

CI 128.278 

SO3 12..522 

0  in  sulphates 2.494 

FcgOg  and  Al^Og 0.004 

SiO^      ..." 0.018 

BO2O3 Trace 

Br  ^ Faint  trace  , 

Total 230.355 

Total  solids  by  evaporation      .  238.12 
<'         "     [duplicate]    .     .     .  237.925 

The  average  composition  of  the  combined  spring  and  stream  waters 
tributary  to  the  lake  cannot  be  stated  with  accuracy,  but  judging  froij^ 

1  A  compilation  of  various  analyses  of  the  water  of  Great  Salt  Lake  and  a  discussion  con- 
cerning them,  is  given  by  G.  K.  Gilbert,  Monograph  No.  1,  U.  S.  Geological  Survey. 

2  School  of  Mines  [Columbia  College]  Quarterly,  vol.  14,  1802,  p.  58. 

3  A  later  determination  showed  about  0.01  gram  of  Br.  in  a  liter. 


82  LAKES    OF    NORTH    A3IERICA. 

such  observations  as  bear  on  the  question,  it  seems  safe  to  assume  that 
their  mingled  waters  would  contain  less  than  double  the  percentage  of 
saline  matter  found  in  the  surface  streams.  The  assumption  that  the 
combined  spring  and  stream  waters  would  contain  about  0.3  part  in  a 
thousand,  or  three  one-hunch-edths  of  one  per  cent  of  total  solids  in  solu- 
tion, seems  as  close  an  approximation  as  can  now  be  reached. 

The  waters  of  the  lake  during  recent  low  stages  have  become  nearly 
saturated  with  sodium  chloride  and  sodium  sulphate,  and  under  certain 
conditions  these  salts  are  precipitated.  The  point  of  saturation  for 
calcium  carbonate  is  passed,  and  this  salt  is  precipitated  probably  as 
rapidly  as  it  is  received.  The  waters  are  not  rich  in  the  compounds  of 
bromine,  boron,  lithium,  and  iodine,  which  frequently  occur  in  "  mother- 
liquors,"  remaining  when  the  more  common  salts  have  been  eliminated  by 
long  concentration,  and  hence  indicating  the  old  age  of  a  lake  containing 
them.  The  recent  analysis  by  Waller,  however,  shows  these  rarer  elements 
to  be  present  in  somewhat  larger  quantities  than  was  previously  supposed. 

The  length  of  time  that  would  be  required  to  charge  Great  Salt  lake 
with  the  common  salt  it  contains,  under  the  present  conditions,  is  estimated 
by  Mr.  Gilbert  at  about  25,000  years. 

The  quantity  of  sodium  chloride,  or  common  salt,  held  in  the  water 
of  the  lake  is  estimated  at  400  million  tons,  and  the  sodium  sulphate  at 
30  million  tons.  These  figures  indicate  the  commercial  importance  of 
this  great  reservoir  of  brine.  The  separation  of  the  common  salt  has 
ali'eady  led  to  a  considerable  industry,  as  from  20  to  40  thousand  tons 
have  been  gathered  yearly  for  a  considerable  period.  The  most  extended 
and  l)est  conducted  of  these  operations  are  carried  on  by  the  Inland  Salt 
Conqjany  at  the  southern  end  of  the  lake.  Evaporating  vats  covering 
more  than  one  thousand  acres  have  been  constructed,  and  are  supplied  by 
pumps  which  deliver  14.000  gallons  of  lake  water  per  minute.  Pumping 
is  continuecl  through  ^lay.  June  and  .July,  and  the  salt  is  ready  for  gather- 
ing in  August.  During  midsummer  the  amount  of  water  evaporated  is 
8,400,000  gallons  daily.  The  yield  of  salt  is  at  the  rate  of  loO  tons  per 
inch  of  water  per  acre.  An  average  season's  yield  is  a  layer  of  salt  about 
seven  inches  thick,  which  would  be  precipitated  from  forty-nine  inches  of 
water.  The  facilities  for  this  industry  may  be  judged  by  the  fact  that 
coarse  salt  packed  on  cars  ready  for  shi])ping,  is  sold  at  the  works  for  one 
dollar  per  ton.  The  mother-liquor  is  allowed  to  go  to  waste,  but  it  is  to 
be  expected  that  sodium  sulphate  and  other  salts  contained  in  it  will  be 
utilized  in  the  near  future. 


EELATION    OF    LAKES    TO    CLIMATIC    CONDITIONS.  83 

Along  the  margin  of  Great  Salt  lake,  where  the  water  is  only  a  few 
inches  deep,  it  l)ecomes  so  concentrated  by  evaporation  that  common  salt 
cry.^tallizes  and  forms  a  brilliant  white  layer  on  the  bottom.  In  fording 
an  arm  of  tht-  lake  about  a  mile  In-oad,  in  order  to  reach  Stansl)ury  island, 
the  writer,  in  1880,  found  a  crust  of  salt  forming  a  glistening  pavement 
strong  enough  to  support  a  horse  and  rider,  but  occasionally  it  would 
give  way  and  lead  to  uncomfortable  flounderings  in  the  black  mud 
beneath. 

The  solubility  of  sodium  sulphate  is  controlled  largely  by  tempera- 
ture. In  Great  Salt  lake  in  summer  it  is  all  dissolved  and  the  waters  are 
clear,  but  as  cold  weather  approaches  it  separates  and  renders  the  Avaters 
opalescent  and  somewhat  milky  in  color.  In  the  di'pth  of  winter,  wlien 
the  tem[)erature  falls  below  zero  of  the  Fahrenlieit  scale,  as  it  does  at 
times  for  da3^s  together,  this  salt  se))arates  in  great  abundance  and  is 
thrown  ashore  by  the  waves  in  hundreds  of  tons,  forming  a  slush-like 
mass  on  the  beach  looking  like  soft  snow.  On  such  occasions  it  can  be 
gathered  in  practically  unlimited  (juantities,  but  is  soon  re-dissolved  when 
the  temperature  rises. 

The  brine  of  the  lake  is  so  concentrated  that  fish  cannot  live  in  it,  but 
it  furnishes  a  congenial  home  for  small  crustaceans  known  as  brine  shrimps 
(Artemia)  and  for  the  larvae  of  dipterous  insects.  These  are  abundant 
at  certain  seasons,  but  not  in  such  vast  numbers  as  in  some  of  the  more 
alkaline  lakes  on  the  west  side  of  the  Great  Basin.  It  has  been  stated 
that  the  vast  num1)ers  of  crustaceans  and  of  larvae  in  these  waters  are  due 
to  the  fact  that  there  are  no  fishes  or  other  animals  in  the  lakes  that 
could  pre}'  upon  them  ;  aquatic  birds,  however,  feed  upon  them  in  great 
numbers,  but  still  they  swarm  in  countless  myriads.  Their  food  seems 
to  be  minute  algae  of  which  several  species  have  been  described. 

As  shown  by  the  analysis  given  above,  the  principal  salt  in  Great  Salt 
Lake  is  sodium  chloride.  In  the  second  example  of  the  saline  lakes 
described  below  the  characteristic  ingredients  are  sodium  carbonate  and 
sodium  sulphate.  Great  Salt  lake  may  be  said  to  be  a  salt  lake  in 
distinction  from  a  number  of  water  bodies  situated  especially  on  the 
west  side  of  the  Great  Basin,  which  may  with  propriety  be  designated 
as  alkaline  lakes. 

Mono  lake,  California.  —  This  lake,  selected  as  the  type  of  a  series 
of  strongly  alkaline  water-bodies  in  the  desert  basins  of  the  Arid  region, 
is  situated  in  south-eastern  California,  within  a  few  miles  of  the  Nevada 


84  LAKES    OF    NORTH    AMERICA. 

boundary.  It  lies  at  the  immediate  eastern  base  of  the  Sierra  Nevada, 
from  which  it  receives  practically  all  of  its  water  supply,  and  occupies 
one  of  the  minor  basins  composing  the  great  area  of  interior  drainage 
known  as  the  Great  Basin.  Its  position  on  the  west  side  of  the  Great 
Basin  and  at  the  base  of  the  great  fault  scarp  forming  the  precipitous 
eastern  slope  of  the  Sierra  Nevada,  is  similar  to  the  situation  of  Great 
Salt  Lake  on  the  east  side  of  the  same  broad  desert  area,  and  at  the  west 
base  of  the  magnificent  fault  scar[)  forming  the  abrupt  western  face  of  the 
Wasatch  range.  Mono  lake,  like  many  other  enclosed  water  bodies  of 
the  Arid  region,  is  of  ancient  lineage,  as  is  shown  by  numerous  beach 
lines,  carved  by  former  water  bodies,  on  the  inner  slopes  of  this  valley. 
The  highest  of  these  lines  is  from  670  to  680  feet  above  the  present  Avater 
surface. 

The  hydrographic  basin  of  Mono  lake  has  an  area  of  nearly  7000 
square  miles,  and,  as  in  the  case  of  the  region  draining  to  Great  Salt  lake, 
is  divided  into  two  strongly  contrasted  portions.  The  southwestern  part 
is  mountainous  and  rugged,  and  bristles  with  serrate  peaks  that  rise  over 
six  thousand  feet  above  the  lake's  surface.  On  the  mountains  the  snow- 
fall is  abundant,  and  several  small"  glaciers  exist  in  the  higher  valleys. 
The  eastern  portion  of  the  drainage  basin  is  comparatively  low,  and  is 
arid  and  desert-like  in  character.  Little  rain  falls  on  this  portion  of  the 
basin,  and  there  are  no  perennial  streams.  Only  occasionally  is  there 
sufficient  precipitation  to  produce  a  surface  drainage,  and  normally  the 
rain  water  and  the  water  produced  from  the  melting  of  the  light  winter 
snows,  is  absorbed  at  once  by  the  thirsty  soil  or  returned  to  the  atmosphere 
by  evaporation. 

To  gain  a  comprehensive  idea  of  the  geography  of  the  interesting 
region  about  Mono  lake,  one  should  climb  some  commanding  summit  on 
the  High  Sierras,  on  its  southwestern  border,  and  study  the  magnificent 
panorama  spread  out  at  his  feet.  Let  the  reader  come  with  me  to  the 
summit  of  Mt.  Dana,  named  in  honor  of  the  venerable  J.^D.  Dana,' one 
of  the  most  prominent  peaks  overlooking  Mono  lake,  and  I  will  endeavor 
to  point  out  some  of  the  more  interesting  features  of  the  land  we  are 
studying.  * 

The  summit  we  have  reached  is  nearly  13,000  feet  above  the  sea.  The 
only  neighboring  mountains  exceeding  it  in  altitude  are  Mt.  Lyell  and 
Mt.  Ritter,  which  rise  with  dazzling  whiteness  against  the  southern  sk}^ 
From  our  station  the  entire  Mono  basin  is  in  view,  and  much  of  it^  his- 
tory can  be  read  as  from  a  printed  page.     We  are  standing  on  one  of  the 


RELATION    OF    LAKES    TO    CLIMATIC    CONDITIONS.  85 

highest  points  on  the  rim  of  a  sharply  defined  hydrographic  basin.  The 
drainage  from  all  directions  tends  towards  the  center  and  forms  a  lake 
from  which  the  waters  escape  only  by  evaporation.  We  can  trace  nearly 
the  entire  boundary  line  of  the  basin,  for  the  reason  that  the  slopes  are  so 
plainly  marked  and  the  crest  lines  so  sharply  drawn,  that  there  is  no  doubt 
as  to  the  direction  that  surface  water  would  take.  The  courses  of  the 
swift,  bright  stream  descending  the  iflountain  can  be  followed  from  their 
sources  in  melting  snow-fields,  down  througli  deep  canons  to  where  they 
enter  the  lake.  On  the  desert  side  of  the  basin,  however,  there  are  no 
streams,  and  but  indefinite  traces  of  the  dry  beds  of  former  water-courses. 
There  is  no  notch  in  the  rim  of  the  basin  to  suggest  a  former  outlet.  The 
only  possible  point  of  discharge  for  the  waters  when  the  ancient  beaches 
scoring  the  inner  slopes  of  the  valley  were  formed,  is  far  to  the  north,  and 
concealed  from  view.  Apparently  at  our  feet,  l)ut  in  reality  a  mile  in 
vertical  descent  below,  lies  the  lake,  a  silent  and  motionless  plain  of  blue. 
Should  the  wind  chance  to  be  strong  in  the  valley,  however,  its  surface 
would  be  ruffled,  the  flash  of  l)reaking  waves  would  reach  the  eye,  and 
long  lines  of  froth  would  streak  its  surface.  At  such  times  abroad  fringe 
of  snowy  foam,  produced  by  the  churning  of  the  alkaline  waters,  encircles 
the  shores  and  renders  their  outlines  unusually  distinct.  Apparently 
floating  on  the  surface  of  the  lake,  there  are  two  conspicuous  islands,  the 
forms  of  which  show  that  they  are  of  volcanic  origin.  That  these  craters 
Avere  built  since  the  encircling  waters  fell  below  their  level,  is  shown 
by  their  unbroken  contours  and  by  the  absence  of  terraces  on  their  outer 
slopes. 

Beyond  the  lake  the  brown  and  barren  land  seems  low  and  feature- 
less, because  of  the  elevation  of  our  point  of  view.  We  can  see  far  be- 
yond the  limits  of  the  drainage  basin,  in  which  we  are  now  specially 
interested,  and  distinguish  many  of  the  desert  ranges  of  Nevada  rising 
above  the  purple  haze  enshrouding  their  bases  and  obscuring  the  lifeless 
lands  between.  The  highest  of  these  distant  summits,  which  appears  like 
a  spectral  mountain  floating  in  the  sky,  is  even  higher  than  the  peak 
on  which  we  stand,  but  its  naked  sides  are  scorched  to  a  cinder-like 
redness  by  the  desert  heat,  and  no  silvery  stream  can  be  detected  in 
the  wild  gorges  scoring  its  flanks.  Its  summit  is  seldom  cloud-capped, 
and  only  in  the  depth  of  winter  is  its  ruggedness  concealed  by  a 
mantle  of  snow. 

To  the  right  of  the  lake  is  a  long  range  of  craters  built  of  fragments 
of  volcanic   rock   thrown   out  during   many  violent  eruptions,  and  now 


86  LAKES    OF    :5rOHTH    AMERICA. 

forming  conical  piles  with  gracefully  sweeping  outlines.  Several  of  these 
now  silent  volcanoes  rival  Vesuvius  in  height  and  beauty,  but  from  our 
elevated  stations  we  can  look  down  upon  the  depressions  in  their  summits, 
and  the  entire  range,  although  two  miles  in  length,  with  peaks  rising 
three  thousand  feet  above  the  lake  that  bathes  its  feet,  is  but  a  minor 
feature  in  the  extended  landscape. 

Northwest  and  southeast  from  the  summit  of  Mt.  Dana  the  crest  line 
of  the  Sierras  is  marked  by  mountain  after  mountain  as  far  as  the  eye  can 
reach.  Turning  south  we  have  in  view  a  fine  example,  though  not  the 
very  finest,  of  the  wild  and  rugged  High  Sierras.  At  the  western  base  of 
the  Mount  Dana  there  is  a  deep,  picturesque  valley,  dotted  with  lakes 
and  traced  by  gleaming  streams.  Like  nearly  all  of  the  more  pronounced 
depressions  in  the  High  Sierras,  this  valley  owes  its  origin  principally  to 
stream  erosion,  and  is  a  relic  of  an  ancient  drainage  system,  but  has 
been  enlarged  and  its  minor  features  modified  l)y  ice  abrasion.  At  one 
time  it  was  occupied  by  a  glacier,  which  formed  a  part  of  a  great  system  of 
ice  fields  that  covered  all  of  the  High  Sierras  and  sent  many  ice  streams 
both  to  the  east  and  west,  through  precipitous  gorges  to  the  valleys 
below. 

The  rocks  forming  the  nearer  slopes  as  one  looks  toward  the  more 
rugged  portion  of  the  range  are  of  varied  character  and  rich  in  color ;  but 
farther  within  llic  heart  of  the  mountains  the  monotonous  gray  coloring 
of  granite  is  but  partially  concealed  by  the  scanty  forests  in  the  canons 
and  valleys,  or  by  the  mosses  and  lichens  on  the  higher  summits.  Near 
at  hand,  but  across  a  deep  intervening  valley,  rises  Mt.  Conness,  bare, 
rugged,  and  grand.  Twelve  miles  to  the  south,  across  a  fragment  of 
deeply  eroded  table-land,  named  the  Kuna  crest,  are  the  spire-like  peaks 
of  Mts.  Lyell  and  Hitter.  Throughout  the  year  their  summits  are  white 
with  snow,  and  small  glaciers  can  be  distinguished  in  tlie  folds  of  theii- 
rugged  sides.  Returning  from  this  vision  of  wild  magnificence,  the  eye 
rests  upon  a  scene  humbler  in  its  charms  but  not  less  pleasing.  Between 
the  naked  crags  forming  the  summit  from  which  we  have  gained  our  com- 
manding view,  and  the  highest  limit  of  the  pines,  all  twisted  and  deformed 
from  unequal  struggles  with  wind  and  drifting  snow,  there  is  a  belt  of 
rugged  precipices  and  weather-beaten  rocks  that  at  certain  seasons  are 
bright  with  lichens  and  fringed  with  the  purple  and  gold  of  alpine  blos- 
soms. These  charming  decorations  on  the  mountain's  brow  flourish  with 
rank  luxuriance  in  every  cranny  and  cleft,  and  not  infrequently  are  in 
such  rich  profusion   that  an   entire  summit-peak  is   tinted  by   them  as 


KELATION    OF    LAKES    TO"  CLIMATIC    CONDITIONS.  87 

with  a  twilio'ht  glow.  In  these  elevated  regions  May-day  is  a  festival  of 
late  summer,  but  it  brings  with  it  a  multitude  of  charms  that  are  unknown 
to  dwellers  in  the  world  below. 

The  mountains  hold  out  innumerable  charms  to  detain  us,  but  we 
must  descend  in  our  fireside  journey,  and  learn  more  of  the  strange  lake, 
the  setting  of  which  was  revealed  from  our  station  on  the  mountain  top. 
Our  downward  journey  is  through  a  deep  gorge  with  nearly  vertical  walls  ; 
in  its  bottom  a  swift,  clear  stream  plunges  from  ledge  to  ledge,  and  rushes 
through  rocky  chasms  with  a  roar  that  never  allows  the  echoes  of  the 
cliffs  a  moment's  pause.  This  pure  stream  of  cold,  delicious  water  reveals 
the  character  of  many  creeks  and  rivulets  that  are  rushing  dow^i  the 
mountain  side  to  the  ever-thirsty  valley  below. 

A  few  springs  add  tlieir  waters  to  the  supply  from  the  mountains, 
but  none  of  them  are  saline,  and  their  united  volume  is  far  less  than  the 
volum,e  of  any  one  of  half-a-dozen  of  the  mountain  torrents  pouring  into 
Mono  lake.  The  present  density  of  the  lake  water  is  the  result  of  the 
long  concentration  by  evaporation  of  the  supply  from  the  mountains. 

The  area  of  Mono  lake  in  the  summer  of  1883,  was  87  square  miles, 
but  varies  Avith  the  seasons  and  also  from  year  to  year.  As  may  be 
learned  from  the  accompanying  map,  its  north  and  south  axis  measures 
11,  and  its  east  and  west  axis  11  miles.  Its  surface  is  broken  by  two 
volcanic  islands  and  l)y  numerous  crags,  some  of  which  are  remnants  of 
islands  now  nearly  eroded  away,  while  others  are  formed  of  calcareous 
deposits  precipitated  about  suljmerged  springs.  The  soundings  given 
on  the  map,  show  that  its  maximum  depth  is  152  feet,  and  the  mean 
depth  about  61  or  62  feet.  Its  elevation  above  the  sea,  when  surveyed 
in  1885,  Avas  6380  feet. 

In  Pleistocene  times,  when  great  glaciers  descended  from  the  High 
Sierras  and  were  prolonged  several  miles  into  the  valley,  the  ratio  between 
inflow  and  evaporation  was  changed,  and  the  lake  rose,  but  never  suffi- 
ciently to  discover  an  outlet.  During  the  time  of  its  greatest  expansion, 
it  had  an  area  of  316  square  miles,  and  formed  an  unbroken  water  surface 
28  miles  long  from  north  to  south,  and  18  miles  broad.  Its  maximum 
depth  was  then  over  800  feet. 

The  facts  of  greatest  interest  in  connection  with  Mono  lake  are  to  be 
found  in  its  chemical  history.  As  shown  in  the  analysis  of  its  waters 
given  on  page  72,  it  is  strongly  impregnated  with  sodium  and  with  car- 
bonic and  sulphuric  acids.  The  most  probable  combination  of  these  and 
other  substances  present  in  the  waters  is  given  below  : 


88 


LAKES    OF    NORTH    AMERICA. 


Hypothetical  Composition  of  the  Water  of  Mono  Lake. 

By    T.    M.    (HATARD.l 


CONSTITCEXTS. 

Grams  ix  a  Liter. 

Pee  cent  of  Total 
Solids. 

Silica,  SiOg 

0.0700 

0.13 

Aluminum  and  ferric  oxide  (AUFe.,)  O3 

0.00:iO 

0.005 

Calcium  carbonate,  CaC()3   . 

0.0050 

0.09 

Magnesium  carbonate,  MgCOg 

0.1028 

0.36 

Sodium  borate,  Xa^B^O- 

0.-2071 

0.39 

Potassium  chloride,  KCl 

1.8365 

3.44 

Sodium  chloride,  NaCl. 

18.5033 

34.60 

Sodium  sulphate,  XaaSO^      . 

9.8«90 

18.45 

Sodium  carbonate,  XaoCOg  . 

18.3556 

34.33 

Sodium  bicarbonate,  XallCOg 
[Specific  gravity,  1.045.] 

4.38.56 

8.20 

53.4720 

100.00 

As  may  be  seen  in  the  above  table,  sodium  carbonate  and  l)iearbonate 
form  42.53  per  cent  of  the  total  salts  held  in  solution.  The  total  quan- 
tity of  these  salts  contained  in  the  lake  is  estimated  at  92  million  tons, 
the  total  saline  content  l)eing  245  million  tons. 

Owing  to  the  cost  of  transportation  and  the  liigh  price  of  labor,  this 
brine  is  not  now  utilized,  but  it  forms  a  reservoir  that  may  be  drawn  upon 
in  the  future.  The  waters  of  Owens  lake,  situated  a  hundred  miles  south 
of  IMono  lake,  where  the  commercial  conditions  are  somewhat  more  favor- 
able, is  already  the  basis  of  a  large  soda  industry.  Two  small  lakes  on 
the  Carson  desert,  known  as  the  Ragtown  ponds,  or  Soda  lakes,  also 
furnish  large  quantities  of  sodium  carbonate  and  bicarbonate.  There  are 
also  several  other  lakes  of  the  same  general  character  in  the  western  part 
of  the  Great  Basin  which  have  not  yet  been  found  of  economic  impor- 
tance. One  of  the  most  promising  of  these,  from  a  commercial  point  of 
view,  is  Soap  lake,  in  the  State  of  Washington. 

The  great  abundance  of  sodium  carbonate  and  bicarbonate  in  Owens, 
Mono,  and  other  lakes  on  the  west  side  of  the  Great  Basin,  in  contrast 
with  the  amount  of  these  salts  in  the  brine  of  Great  Salt  lake  and  of  other 
similar  water  bodies  on  the  east  side  of  the  Great  Basin,  is  due  mainly  to 
differences  in  the  character' of  the  rocks  of  the  two  regions.  The  moun- 
tains on  the  west  are  largely  formed  of  volcanic  rocks,  and  yield  alkaline 
1  Amer.  Jour.  Sci.,  3d  Ser.,  vol.  36,  1888,  p.  149. 


RELATION    OF    LAKES    TO    CLIMATIC    CONDITIONS.  89 

salts  to  the  waters  flowing  over  them  or  percolating  through  their  inter- 
stices ;  while  the  rocks  of  the  eastern  area  are  largely  sedimentary  in 
origin,  and  su[)ply  sodium  chloride  in  excess  of  sodium  carl)onate. 

The  chemical  history  of  the  lakes  of  the  Arid  region  is  not  only  an 
interesting  and  attractive  study,  but  one  of  great  economic  importance, 
as  they  hold  an  almost  unlimited  supply  of  common  salt,  and  of  sodium 
carbonate  and  bicarbonate,  sodium  sulphate,  and  other  salts  in  less  abun- 
dance. This  supply  is  still  farther  augmented  by  the  deposits  of  former 
lakes  now  evaporated  to  dryness.  The  salts  precipitated  from  these  ex- 
tinct lakes,  in  some  instances,  whiten  the  surfaces  of  desert  valleys,  but 
more  frequently  they  are  buried  beneath  or  absorbed  in  the  clays  forming 
the  smooth  plains  left  by  the  evaporation  of  playa  lakes. 

The  importance  of  the  lakes  of  the  Arid  region  to  those  interested  in 
salt  and  alkali  industries  is  so  great  that  the  table  on  page  72  has  been 
inserted  to  show  the  comparative  values  of  the  brines  thus  far  analyzed. 
More  detailed  information  in  this  connection  may  be  found  in  the  publi- 
cations cited  below. 1 

1  G.  K.  Gilbert,  "Lake  Bonneville,"  U.  vS.  Geol.  Surv.,  Monograph  No.  1.  —I.  C.  Russell, 
"Lake  Lahontan,"  U.  S.  Geol.  8urv.,  Monograph  No.  11.  — I.  C.  Kussell,  "Lake  Mono," 
U.  S.  Geol.  Surv.,  8th  Ann.  Rep.,  1880-87,  pp.  287-299.  —I.  C.  Russell,  "  Reconnoissance  in 
Washington,"  U.  S.  Geol.  Surv.,  Bulletin  No.  108. —T.  M.  Chatard,  "Natural  Soda,"  U.  S. 
Geol.  Surv.,  Bulletin  No.  60. — T.  M.  Chatard,  "Analyses  of  the  \Vater  of  Some  American 
Alkaline  Lakes,"  Am.  Jour.  Sci.,  3d  Ses.,  vol.  36,  1888,  pp.  146-150. —T.  M.  Chatard, 
"Urano,"  Am.  Jour.  Sci.,  3d  Ses.,  vol.  38,  1889,  pp.  59-66. —  J.  E.  Talmage,  "The  waters 
of  Great  Salt  Lake,"  Science,  vol.  14,  1889,  pp.  444-446.  —  E.  AValler,  "Analysis  of  the 
Water  of  Great  Salt  Lake,"  School  of  Mmes  [Columbia  College]  Quarterly,  vol.  14,  1892, 
pp.  56-61. 


CHAPTER   V. 

THE  LIFE  HISTORIES   OF  LAKES. 

Lakes,  like  many  other  features  of  the  earth's  surface,  as  stated 
in  our  introductory  cha})ter,  have  their  periods  of  growth,  adolescence, 
maturity,  decadence,  and  old  age  leading  to  extinction. 

The  lives  of  most  lakes  are  so  long  that  human  records  cover  only  a 
small  portion  of  their  histories,  hence  their  growth  and  decadence  can 
seldom  be  traced  by  observing  a  single  individual.  By  studying  many 
examples,  however,  in  various  stages  of  development  and  decline,  we 
are  enabled  to  obtain  separate  links  in  the  chain  of  their  existence,  and 
may  determine,  at  least  in  outline,  the  general  course  that  they  run.  By 
having  the  theoretical  history  of  a  normal  lake  in  mind,  one  is  enabled  to 
determine  the  period  of  life  attained  by  any  special  example  that  may 
be    studied. 

The  histories  of  all  lakes  are  far  from  uniform.  There  are  various 
accidents,  as  they  may  be  termed,  which  introduce  new  conditions,  and 
may  renew  their  youth  or  hasten  their  decline.  In  general,  lakes  may  be 
grouped  in  two  great  classes,  in  each  of  which  the  role  they  play  is  in 
the  main  the  same.  The  differences  in  the  lives  of  these  two  classes 
depend  mainly  on  climatic  conditions,  and  have  been  noticed  in  describ- 
ing fresh  lakes  and  terrestrial  saline  lakes.  The  destiny  of  a  lake  born 
beneath  humid  skies  runs  in  a  somewhat  definitely  prescribed  channel  and 
departs  in  a  marked  way  from  the  more  varied  life  of  a  lake  originating  in 
an  arid  region.  The  general  outline  of  the  history  of  each  of  the  two 
classes  referred  to  is  briefly  as  follows : 

Lakes  of  Humid  Kegions.  —  The  normal  lakes  of  humid  regions 
are  comparatively  short-lived.  The  streams  tributary  to  them  bring  in 
sediments  which  tend  to  fill  their  basins,  to  these  are  added  the  ddbris 
of  water-loving  plants  and  the  hard  parts  of  animals,  and  at  the  same 
time  the  streams  flowing  from  them  tend  to  cut  down  their  outlets  and 
drain  them  at  lower  and  lower  levels.  Two  processes  thus  conspire  to 
diminish  their  volumes  and  shorten  their  existence.  The  deposition  of 
sediment  on  their  bottoms  usually  leads  to  their  extinction  more  quickly 


THE    LIFE    HISTORIES    OF    LAKES.  91 

than  the  lowering  of  their  outlets,  for  the  reason  that  while  incoming 
streams  are  frequently  turbid  and  heavy  with  sediment,  the  outgoing 
waters  are  clear  and  therefore  have  but  little  power  to  erode.  The  clear 
outflowing  waters  deepen  their  channels  by  the  slow  process  of  chemical 
solution,  but  when  the  rocks  over  which  they  pass  are  soft  and  inco- 
herent, they  may  soon  become  recharged  Avith  sediment  and  make  rapid 
progress  in  deepening  their  channels  and  in  draining  the  basin  above.  The 
lives  of  various  lalvcs  may  differ  in  length  and  have  minor  variations 
according  to  local  conditions,  but  the  main  features  in  their  histories  will 
conform  to  the  same  general  outline. 

The  filling  of  lake  basins  by  sediment  frequently  progresses  more 
rapidly  than  at  first  might  be  supposed.  In  some  instances  its  rate 
may  be  observed  from  year  to  year,  and  attracts  the  attention  of  even  the 
casual  observer.  In  countries  that  have  been  long  inhabited,  there  is 
sometimes  historical  evidence  of  the  rate  at  which  the  boundaries  of  lakes 
have  contracted.  At  the  head  of  Lake  Geneva,  Switzerland,  for  examjjle, 
the  Rhone  is  bringing  in  large  quantities  of  silt  derived  from  the  gla- 
ciers on  its  head  waters,  and  a  low  grade  delta  is  being  extended  into  the 
lake.  As  stated  by  Lyell,^  the  town  of  Port  Vallais  (Portus  Valesa;  of 
the  Romans)  once  situated  at  the  water's  edge,  is  now  more  than  a  mile- 
and-a-half  inland,  this  extension  of  the  shore  having  been  made  in 
about  eight  centuries. 

The  decrease  in  the  capacity  of  lake  basins,  in  ordinary  cases,  goes  on 
so  much  more  rajndh^  from  filling  than  from  the  lowering  of  their  outlets, 
that  it  is  the  destiny  of  most  lakes  situated  in  humid  regions  to  become 
exterminated  mainly  by  sedimentation.  By  this  process  their  basins  are 
transformed  into  alluvial  plains,  through  which  wander  the  streams  that 
were  tributary  to  the  antecedent  lakes.  These  streams  being  no  longer 
robbed  of  the  material  they  carry  in  suspension,  are  enabled  to  attack 
their  channels  below  the  former  lakes  with  energy,  and  to  deepen  and 
broaden  them.  The  grade  of  the  streams  through  the  alluvial  plain, 
marking  the  former  site  of  a  lake,  is  increased,  and  the  removal  of  the 
soft  lakebeds  progresses  as  the  channel  below  is  deepened.  Streams  flow 
through  alluvial  plains  with  slackened  speed,  and  form  Avinding  channels, 
and  swing  from  side  to  side  of  their  valleys,  thus  reducing  the  general 
level.  The  load  previously  deposited  in  the  basin  is  again  taken  up  and 
the  deferred  task  of  transporting  it  to  the  sea  is  resumed.     Former  lake- 

1  Principles  of  Geology,  11th  edition,  1873,  vol.  1,  p.  413. 


92  LAKES    OF    NORTH    AMERICA. 

basins  thus  become  terraced  valleys,  with  streams  winding  through  them 
in  broad  curves,  and  in  civilized  regions  afford  rich  farming  lands  and 
charming  sites  for  towns  and  cities. 

At  a  later  period,  if  some  outside  influence  does  not  change  the  course 
of  histoiy,  the  alluvial  deposits  are  dissected  to  the  bottom,  the  terraces 
of  soft  material  are  removed,  and  all  records  of  the  once  beautiful  lake 
may  be  lost.  This  transformation  may  require  tens  of  thousands  of  years 
for  its  completion,  yet  the  end  is  inevitable.  The  various  stages  in  this 
general  history  might  be  illustrated  l)y  an  abundance  of  examples.  Tliou- 
sands  of  lakes  in  the  formerly  glaciated  region  of  northeastern  America 
still  retain  the  freshness  of  youth,  and  their  nearly  level  bottoms  may  be 
considered  as  unborn  lacustral  plains.  The  terraced  borders  of  Lake  Cham- 
plain,  and  of  the  Laurentian  lakes,  mark  the  former  extent  of  water 
bodies  that  have  passed  the  youthful  stage.  Many  terraced  valleys  in  the 
Cordilleras  record  the  former  presence  of  lakes  in  basins  that  are  now 
completely  drained.  In  other  localities,  as  in  the  "  Parks  "  of  Colorado, 
no  terraces  may  be  distinguished,  but  vestiges  of  lacustral  sediment  still 
floor  their  bottoms.  Many  valleys  in  the  same  region  drain  through 
narrow  stream-cut  gorges,  but  all  other  evidence  of  their  having  been 
formerly  water-filled  lias  vanished.  The  time  required  for  these  muta- 
tions is  vast  Avhen  reckoned  in  yeare,  but  to  the  geologist  they  are 
transient  phases  in  the  topographic  development  of  the  land. 

The  even  coui"se  of  history,  outlined  above,  may  be  varied  somewhat, 
as  when  the  outflowing  stream  is  rapid  and  especially  when  falls  occur  in 
its  course.  Waterfalls  are  fonned  especially  where  streams- flow  over 
nearly  horizontal  strata  where  a  hard  surface  layer  rests  upon  shales  or 
other  easily  eroded  beds,  as  is  typically  illustrated  at  the  Falls  of  Niagara. 
The  undermining  of  the  hard  capping  layer  is  effected  by  the  removal  of 
the  soft  beds  beneath,  and  blocks  from  the  brink  of  the  precipice  fall  to 
the  pool  below  and  assist  the  swirling  water  to  deepen  a  basin.  A  fall 
thus  cuts  back  the  ledge  over  which  it  plunges  with  comparative  rapid- 
ity, —  in  the  case  of  Niagara  the  rate  of  recession  is  from  4  to  6  feet  per 
year,  —  and  may  lead  to  the  drainage  of  a  lake  before  its  basin  has  been 
deeply  filled  with  sediment.  The  succession  of  the  principal  events  in  the 
history  of  a  valley  may  thus  be  hastened,  but  the  ultimate  results  will  be 
essentially  the  same. 

Many  small  lakes,  especially  in  forested  countries,  where  the  surface 
waters  filter  through  layers  of  vegetal  )le  debris  before  gathering  into  rills 
and  brooks,  are  filled  mainly  by  organic  agencies.     Water  plants,  and 


THE   LIFE    HISTORIES    OF   LAKES.  93 

especially  Sphafjmim  or  peat  moss,  grow  about  their  shores,  and  extend- 
ing outward,  form  a  thick  mat  of  intertwined  roots  and  stems  tliat  float  on 
the  surface.  The  finer  waste  from  this  sheet  of  floating  verdure  falls  to 
the  bottom  and  forms  a  peaty  stratum.  To  this  layer  contributions  are 
made  l)y  other  aquatic  vegetation,  as  the  lilies,  reeds,  rushes,  and  many 
beautiful  sul>aquatic  plants.  It  also  receives  the  trunks  of  trees  falling 
from  tlie  shore.  The  small  lakes  of  the  prairie  region  especially,  are  fre- 
quently transformed  in  this  manner  into  beautiful  fields  of  wild  rice.  In 
the  central  part  of  moss-encircled  lakes,  practically  no  mechanical  sedi- 
ments are  deposited,  but  mollusks,  crustaceans,  and  fishes  may  there  find 
a  well  sheltered  home  and  thrive  in  such  abundance  that  the  bottom  soon 
becomes  covered  with  their  remains.  Microscopic  forms  also  inhaljit  the 
Avater  and  their  siliceous  cases  frequenth'  accumulate  so  as  to  form  tliiek 
layers,  known  as  diatomaceous  earth.  A  continuation  of  this  process  under 
favorable  conditions  leads  to  the  rapid  extinction  of  small  lakes.  The  open 
waters  are  converted  into  bogs  and  swamps,  on  which  forest  trees  encroach 
and  still  farther  assist  in  the  transformation.  When  these  deposits  of 
organic  matter  are  drained,  they  frequently  furnish  rich  garden  lands. 
The  lakes  exterminated  by  this  organic  process  in  the  drift-covered  por- 
tion of  North  America,  can  only  be  estimated  in  tens  of  thousands,  and 
probably  equal  in  number  the  lakes  still  remaining. 

Lakes  of  Arid  Reg-ion.s.  —  On  every  continent  there  are  broad  areas 
where  the  skies  are  without  a  storm  cloud  for  many  months  each  year  and 
the  air  is  dry  and  hot  in  all  l^ut  the  winter  season.  The  lakes  in  these 
desert  regions  have  a  different  general  history  from  their  sisters  whose 
banks  are  fringed  with,  green  vegetation  and  overshadowed  by  forests. 
Where  the  rainfall  is  small  and  evaporation  active,  the  lives  of  lakes 
depend  on  delicate  adjustments  of  climatic  conditions.  As  the  barometer 
rises  and  falls  in  harmony  with  changes  in  atmospheric  pressure,  so  en- 
closed lakes  fluctuate  in  sympathy  with  changes  in  humidity  or  in  tem- 
perature. The  ephemeral  lives  of  playa  lakes  have  already  been  described, 
but  the  larger  lakes  of  arid  regions,  although  subject  to  many  fluctuations, 
may  have  a  longer  span  of  existence  than  lakes  of  corresponding  size  and 
similar  topographic  environment  in  humid  regions.  As  enclosed  lakes  do 
not  overflow,  there  is  no  loss  of  area  owing  to  the  lowering  of  outlet. 
Tributary  streams  bring  in  material  both  in  solution  and  in  suspension,  all 
of  which  is  left  as  evaporation  progresses,  and  tends  to  fill  their  basins, 
but  the  volume  of  their  waters  is  not  directly  diminished  by  this  process. 


94  LAKES    OF    NORTH    AMElilCA. 

As  their  basins  are  filled,  however,  the  waters  expand  and  offer  a  greater 
surface  to  the  atmosphere,  thus  promoting  evaporation.  A  continuance 
of  this  process  results  in  so  enlarging  the  water  surface  that  in  time  evap- 
oration equals  the  supply  and  the  water  body  passes  to  the  condition  of  a 
playa  lake.  Sedimentation  may  raise  the  water  surface  so  that  an  outlet 
is  found  before  the  playa  stage  is  reached,  thus  transferring  an  enclosed 
and  saline  lake  to  the  class  normal  to  humid  regions,  already  considered. 

The  existence  of  lakes  in  countries  where  there  is  a  close  adjustment 
between  precipitation  and  evaporation,  is  also  controlled  largely  by  topo- 
graphic conditions.  It  may  be  said  that  this  is  the  primary  condition  that 
determines  whether  lakes  shall  exist  in  arid  regions  or  not.  This  is  true, 
if  Ave  consider  the  origin  of  the  lake  basins,  and  also  important  if  the  ex- 
istence of  lakes  in  ready-formed  basins  is  discussed,  since  the  topography- 
has  a  direct  and  frequently  controlling  influence  on  rainfall  and  on  evapo- 
ration. The  influence  of  topography  is  also  marked  in  determining  the 
ratio  of  the  area  of  a  basin  to  the  area  of  the  lake  in  its  lowest  depres- 
sion. The  hydrographic  basins  of  enclosed  lakes  as  a  rule  are  large  in 
reference  to  their  water  surfaces,  when  compared  with  the  ratio  of  catchment 
areas  to  lake  areas  in  humid  regions.  Any  change  tending  to  diminish 
the  area  tributary  to  an  enclosed  lake,  as  the  sapping  of  the  head  waters  of 
its  tributary  streams,  would  have  a  marked  influence  on  its  history. 

Episodes  of  another  character  also  occur  in  the  lives  of  enclosed  lakes. 
The  salts  slowly  accumulated  in  them  may  not  only  be  flooded  out  by 
overflow  consequent  on  changes  in  topography,  or  on  an  increase  in  rain- 
fall, or  on  a  decrease  in  evaporation,  but  may  be  eliminated  by  reason  of  a 
reverse  change  in  the  ratio  of  inflow  to  evaporation.  A  decrease  in  humid- 
ity or  an  increase  in  evaporation,  or  what  is  probably  more  frequent,  a 
combination  of  these  two  processes,  may  reduce  a  lake  to  the  playa  stage. 
When  this  occurs,  its  salts  will  be  precipitated  and  may  become  buried  or 
absorbed  by  sediment,  so  that  when  a  new  lease  of  life  is  granted  and  the 
waters  expand  and  form  a  perennial  lake,  they  are  fresh,  or  essentially 
so,  and  start  anew  in  the  process  of  concentration.  Still  other  changes 
that  beset  the  lives  of  enclosed  lakes  might  be  enumerated,  to  show  that 
they  are  subject  to  greater  vicissitudes  than  their  sister  lakes  in  more 
favored  lands. 

When  the  lakes  of  arid  regions  become  extinct,  either  by  reason  of 
evaporation  or  sedimentation,  the  evidence  of  their  former  existence 
remains  inscribed  on  the  inner  slopes  of  their  liasins  or  concealed  in  the 
strata  deposited  over  their  bottoms.     These  records  as  a  rule  are  much 


THE   LIFE    HISTORIES    OF    LAKES.  95 

more  lasting  tlian  those  left  by  lakes  in  humid  lands,  for  the  reason  that 
the  climatic  conditions  are  less  destructive.  The  terraces  and  emljank- 
ments  of  gravel  left  l)y  lakes  in  desert  valleys  are  especially  permanent 
topographic  features,  as  the  scanty  rain  that  falls  on  them  is  absorbed  and 
allowed  to  percolate  slowly  through  them,  instead  of  flowing  down  their 
surfaces  so  as  to  erode.  The  sediments  deposited  in  enclosed  basins  are 
also  protected  from  destruction,  as  they  cannot  be  removed  by  streams 
until  some  change  inaugurates  free  drainage  to  the  sea  or  to  some  lower 
basin.  A  continuation  of  aridity  in  a  desiccated  lake  basin,  results 
normally  in  the  burial  of  the  lacustral  sediments  beneath  subaerial 
deposits,  .thus  again  insuring  their  preservation.  To  follow  this  subject 
farther  would  lead  to  a  comparative  study  of  the  processes  of  erosion  in 
arid  and  in  humid  regions,  which  is  beyond  the  scope  of  the  present  essay. 

It  will  be  seen  from  what  has  been  presented  above  with  reference  to 
the  normal  course  of  the  lives  of  lakes,  that  in  spite  of  the  many  varia- 
tions they  present,  the  seeds  of  death  are  planted  at  their  birth,  and  they 
are  destined,  sooner  or  later,  to  pass  away  and  give  place  to  other  condi- 
tions. 

Interruptions  of  the  even  tenor  of  the  lives  of  lakes,  in  both  arid  and 
humid  regions,  such  as  the  effects  of  upheaval  and  depression  of  the  earth's 
crust,  earthquakes  and  volcanic  eruptions,  might  be  considered,  but 
these  abnormal  incidents,  like  the  accidents  in  human  lives,  cannot  be 
foretold,  and  apply  to  individuals  rather  than  to  classes. 


CHAPTER    VI. 

STUDIES    OF    SPECIAL    LACUSTRAL    HISTORY. 

It  will  appear  to  the  reader  of  the  preceding  chapter  that  not  only 
are  lakes  ephemeral  features  of  the  earth's  surface,  but  even  the  changes 
they  make  in  the  topography  of  their  shores,  although  perhaps  engraved 
in  solid  rock,  are  of  short  duration  in  comparison  Avitli  the  length  of  the 
eras  into  which  the  earth's  history  has  been  subdivided.  The  lakes  of 
Pleistocene  times,  however,  left  records  which  in  many  instances  are  still 
legible,  and  form  a  connection  between  historical  and  the  most  recent 
geological  times. 

As  examples  of  extinct  lakes  whose  histories  are  still  clearly  legible, 
a  brief  account  will  be  given  of  forme»  water  bodies  of  the  Laurentian 
basin,  and  in  the  region  now  draining  to  Lake  Winnepeg,  where  the 
climate  is  humid,  and  of  two  formerly  extensive  lakes  of  the  Arid  region. 

PLEISTOCENE    LAKES    OF    THE    LAURENTIAN    BASIN. 

Long  curving  ridges  of  gravel  having  tlie  appearance  of  great  railroad 
eml)ankments,  following  the  general  trend  of  the  shores  of  lakes  Ontario 
and  Erie,  but  usually  at  a  distance  of  several  miles  from  their  present 
borders,  were  noticed  at  an  early  day  in  the  settlement  of  New  York, 
Ohio,  and  Ontario,  and  correctly  interpreted  as  being  the  records  of  previous 
liigh-water  stages  of  the  lakes  tliey  encircle.  These  ridges  became  high- 
ways of  travel  as  civilization  advanced,  and  gave  origin  to  the  term  "ridge 
road "  still  to  be  seen  on  local  maps  of  the  region  referred  to.  These 
ridges  and  other  associated  records  have  claimed  the  attention  of  geolo- 
gists and  others  and  have  been  made  the  subject  of  special  inquiry.  The 
territory  traversed  by  them  is  so  extensive,  however,  that  their  study  is 
still  far  from  complete. 

The  ancient  beaches  about  lakes  Ontario  and  Erie  have  been  followed 
and  studied,  especially  l)v  G.  K.  Gilbert,  in  Xew  York  and  Ohio,  and  by 
J.  W.  Spencer,  in  Canada.  The  records  of  former  water  levels  north  of 
Lake  Superior  from  Duluth  to  Sault  Sainte  Marie,  have  been  traced  and 
mapped  by  A.  C.  Lawson.  To  the  south  of  Lake  Superior  the  ancient 
shores  have  been  systematically  followed  by  F.  B.  Taylor.     Many  other 


STUDIES    OF    SPECIAL    LACUSTKAL    HISTORY.  137 

observers  have  also  contributed  to  this  study,  but  not  in  such  a  methodical 
manner  as  those  whose  names  have  just  been  mentioned.  Some  of  the 
problems  that  have  presented  themselves  during  this  investigation  have 
not  yet  been  satisfactorily  explained,  but  at  least  an  outline  of  the  Pleis- 
tocene history  of  the  Laurentian  basin  may  be  presented  with  the  under- 
standing that  it  is  to  be  modified  as  additional  facts  are  obtained. 

The  most  dramatic  episode  in  the  geological  history  of  North  America 
was  the  formation  during  Pleistocene  time,  of  glaciers  many  hundreds  of 
feet  in  thickness  over  the  northern  part  of  the  continent.  The  ice  advanced 
from  the  north  and  not  only  covered  the  Laurentian  basin,  but  spread 
southward  beyond  the  southern  border  of  its  watershed.  Tlie  ice  covered 
this  region  with  various  advances  and  retreats  for  thousands  of  years,  and 
when  it  finally  withdrew,  the  immediate  ancestors  of  the  present  Great 
Lakes  were  born.  There  are  severe!  observations  tending  to  the  conclu- 
sion that  during  an  interglacial  time  when  the  ice  receded  far  north  of  its 
maximum  limit,  lakes  were  formed  in  the  same  basin,  but  in  this  connec- 
tion there  is  little  evidence  to  claim  popular  attention. 

Previous  to  the  Glacial  epoch  or  the  Great  Ice  age,  as  it  is  frequently 
termed,  the  region  under  review  ^^'as  an  old  land  surface  with  rivers  flow- 
ing across  it  to  the  sea.  Its  drainage  system  was  well  developed  and  the 
streams  meandered  through  broad  valleys,  bounded  in  part  1)}^  steep  escarp- 
ments. In  general  relief,  it  must  have  resembled  the  upper  portion  of  the 
Mississippi  valley  as  it  exists  to-day,  where  the  to[)Ography  has  not  been 
modified  by  glacial  action. 

The  conclusion  that  the  Laurentian  region  was  exposed  to  erosion  for 
a  long  period  previous  to  the  Glacial  epoch,  is  based  on  the  character  of  the 
relief  of  the  hard  rock  surface  now  covered  in  part  by  glacial  deposits  and 
on  the  fact  that  no  sediments  of  younger  date  than  the  Carboniferous 
period,  with  the  possible  exceptions  of  terranes  of  Cretaceous  age  in  por- 
tions of  Minnesota,  occur  witliin  its  borders. 

It  may  be  suggested  as  a  tentative  hypothesis,  that  previous  to  the 
Glacial  epoch  the  greater  part  of  the  Laurentian  basin  discharged  its 
waters  southward  to  the  Mississippi,  and  that  during  the  first  advance  of  the 
ice  from  the  north,  the  drainage  was  not  obstructed  so  as  to  form  important 
lakes.  This  suggestion  rests  in  part  on  the  fact  that  no  lake  deposits 
have  yet  been  found  beneath  the  lowest  sheet  of  glacial  del^ris  lining  the 
basin,  —  this  negative  evidence  is  of  little  Aveight,  however,  as  such 
deposits,  if  the}"  exist,  would  be  mostly  beneath  the  present  lakes  and 
therefore  exceedingly  difficult  to  discover, — and  on  the  character  of  an 


98  LAKES    OF    NOKTH    AMERICA. 

ancient  river  valley  leading  south  from  the  southern  end  of  Lake  Mich- 
igan, which  is  reported  to  be  scored  A^ith  glacial  grooves,  and  obstructed 
by  glacial  deposits. ^  As  will  be  noticed  below,  tliis  same  channel  was  also 
an  outlet  for  the  waters  of  the  Lake  Michigan  basin  in  post-glacial  times. 

When  the  glaciers  of  the  Glacial  epoch  were  at  their  maximum,  the 
drainage  from  the  ice  found  a  free  escape  southward,  as  is  abundantly 
testified  by  immense  deposits  of  gravel  that  were  dropped  by  the  over- 
loaded glacial  streams,  as  well  as  by  numerous  water-worn  channels  whicli 
are  too  large  for  the  streams  now  occupying  them  and  are  Avithout  water- 
sheds commensurate  with  their  size. 

As  the  ice  sheet  retreated,  there  came  a  time  when  its  southern  margin 
was  north  of  the  drainage  divide,  passing  in  an  irregular  east  and  west 
direction  through  Central  New  York  and  Central  Ohio,  and  now  parting 
the  waters  flowing  south  from  those  that  find  their  way  northward  to  the 
Laurentian  lakes.  When  this  occurred,  lakes  were  formed  between  tlie 
margin  of  the  ice  and  the  high  land  to  the  south.  These  earlier  lakes 
stood  at  various  levels  and  discharged  southward  across  the  lowest  depres- 
sions in  their  shores.  Stream  channels  were  excavated  by  the  outflowing 
waters  and  became  deeply  filled  with  gravel  and  sand,  but  in  many  instances 
are  still  clearl}-  traceable.  One  of  these  ancient  channels  starts  near  Fort 
Wayne,  Indiana,  leads  southwest  and  afforded  an  escape  for  the  Avaters  that 
accumulated  in  the  Avestern  portion  of  the  Erie  basin.  A  similar  outlet 
at  the  south  end  of  the  Lake  Michigan  l)asin  has  already  been  referred  to. 
Other  points  of  discharge  have  been  reported  at  other  localities  on  the 
southern  margin  of  the  Laurentian  basin. 

As  the  ice  occupying  the  Erie-Ontario  basin  withdrew  northward, 
the  lakes  about  its  margin  expanded  and  became  united  one  witli  another. 
When  the  ice  barrier  between  the  two  basins  Avas  l)roken  the  higher  lake 
discharged  into  the  lower  one,  and  its  former  outlet  leading  south  Avas 
abandoned. 

When  a  single  Avater  body  occupied  the  Erie-Ontario  basin,  the  site  of 
Niagara  river  Avas  deeply  submerged.  When  the  Avater  fell  to  the  level 
of  the  ^NlohaAvk  outlet,  the  tAvo  basins  became  divided  and  Niagara  river  AA^as 
born.  The  river  from  the  upper  basin  discharged  across  the  lowest  sag 
in  its  rim  and  cut  back  a  deep  gorge,  until  an  old  channel  excaA^ated  in  pre- 
giacial  or  possibh'  inter-glacial  times,  Avas  discovered  and  the  Avork  of 
extendinsr  it  rencAved.     When  the  falls  shall  have  receded  so  as  to  drain 

1  Farther  evidence  seems  to  be  needed,  however,  before  the  presence  of  a  pre-glacial 
channel  leading  south  from  Lake  Michigan,  can  be  considered  as  definitely  determined. 


C5 


STUDIES    OF    SPECIAL    LACUSTRAL    HISTORY.  99 

Lake  Erie  at  a  lower  level  than  at  present,  the  shore  lines  now  forming 
about  its  margin  will  be  abandoned  and  another  line  added  to  the  records 
about  its  borders. 

For  a  long  period  in  the  history  of  the  Ontario  basin,  the  outflowing 
water  escaped  through  the  ]\Iohawk  valley,  New  York,  as  has  been  shown 
by  Gilbert,  and  the  discharge  of  a  large  part  of  the  Laurentian  basin 
reached  the  sea  by  that  channel.  The  series  of  well  defined  water-marks 
about  the  Oiitario  basin  formed  at  this  time,  has  been  named  the  ""  Iroquois 
beach,"  by  Spencer,  and  the  ancient  lake  outlined  by  it  is  known  as  "Lake 
Iroquois."  When  the  ice  front  retreated  still  farther  northward,  tlie 
present  course  of  the  St.  Lawrence  was  uncovered,  the  Mohawk  channel 
was  abandoned,  the  Avater  surface  fell,  and  existing  conditions  were 
established. 

During  various  stages  in  the  enlargement  and  subsequent  contraction 
of  the  lakes  about  the  southern  margin  of  the  Laurenticle  glacier,  beaches 
were  formed  which  in  some  instances,  as  has  been  shown  by  Frank  Lev- 
erett,  in  Ohio,  are  continuations  of  the  moraines  deposited  at  the  margin 
of  the  ice  where  lakes  did  not  exist  in  front  of  it.  In  other  instances 
moraines  ojcur  that  are  partially  or  wholly  buried  beneath  lake  sediments 
and  mark  the  boundaries  of  the  ice  front  where  it  was  margined  by  water 
bodies. 

At  many  localities  where  the  former  water  markings  are  well  pre- 
served, they  were  made  on  low  shores,  and  took  the  form  of  ridges  re- 
sembling railroad  embankmi'uts.  The  highest  of  these  ridges  marks  the 
maximum  limit  of  the  water  body  about  which  it  was  formed.  As  the 
water  fell  the  higher  beaches  were  abandoned  and  others  constructed  at 
levels  determined  by  lower  outlets.  When  the  borders  of  the  lakes  were 
of  ice,  shore  records  are  wanting,  but  as  stated  above,  buried  moraines 
may  mark  the  position  of  the  dividing  line  between  the  water  and  the 
confining  ice. 

While  the  ancient  beaches  were  in  process  of  construction  the  abun- 
dant sediments  carried  into  the  lakes,  were  spread  out  as  sheets  of  clay 
over  the  deeper  portions  of  the  basin,  and  at  the  same  time  the  areas  near 
shore  received  deposits  of  sand.  Icebergs  l)roke  away  from  the  glaciers 
forming  the  northern  shores  of  the  lakes,  and  floated  over  their  surfaces, 
carrying  stones  which  were  dropped  as  the  ice  melted,  and  became  im- 
bedded in  the  clay  on  the  bottom.  These  deposits  surround  the  present 
Laurentian  lakes  and  underlie  them.  About  the  borders  of  Lake  Erie 
they  appear  as  a  stiff  blue  clay, — known  to  geologists  as  the  "Erie  clay," 


100  LAIvES    OF    NOIITH    AMERICA. 

charged  in  some  instances  ^Yith  lai-ge  boulders  of  cr^'stalline  rock,  —  and  as 
siieetsof  yellow  sand,  known  as  "delta  sands,"  which  rest  on  the  clay,  and 
are  especially  abundant  where  the  mouths  of  ancient  streams  were  located. 
About  the  shores  of  Lake  Superior  and  frequently  extending  many  miles 
inland,  there  are  ancient  clay  deposits  of  a  pink  color,  that  were  accumu- 
lated when  the  basin  contained  a  much  larger  sheet  of  water  than  at 
present. 

The  beaches  about  the  borders  of  the  Laurentian  lakes  were  originally 
horizontal,  but  as  has  been  shown  especially  by  Gilbert  and  Spencer,  they 
are  in  many  cases  no  longer  in  their  original  position.  Changes  in  the 
elevation  of  the  land  have  occurred  and  the  beaches  have  been  carried  up 
or  down  with  it. 

The  amount  of  change  in  level  shown  by  the  warping  of  the  beaches 
about  Lake  Ontario  is  considerable,  and  illustrates  the  character  of  the 
slow  upheavings  and  subsidences  known  to  be  in  progress  over  wide  areas 
of  the  earth's  surface.  It  is  stated  by  Gilbert^  that  ''  the  old  gravel  spit 
near  Toronto,  belonging  to  what  is  known  as  the  Davenport  ridge,  is  forty 
feet  higher  than  the  contemporaneous  gravel  spit  on  which  Lewiston  is 
built;  at  Belleville,  Ontario,  the  old  shore  is  200  feet  higher  than  at. 
Rochester  ;  at  Watertown,  X.  Y.,  300  feet  higher  than  at  Syracuse  ;  and 
the  lowest  point  in  Hamilton,  Ontario,  at  the  head  of  the  lake,  is  325  feet 
lower  than  the  highest  point  near  Watertown.  From  these  and  other 
measurements  shown  on  Plate  18,  we  learn  that  the  Ontario  basin  with 
its  new  attitude  inclines  more  to  the  south  and  west  than  with  the  old 
attitudes."  This  general  tilting  has  thrown  the  watery  of  Lake  Ontario 
westward  and  flooded  small  tributary  valleys  so  as  to  drown  them  and 
make  miniature  fiords. 

Movements  in  the  earth's  crust  were  also  in  progress  during  the  long 
period  in  which  the  ancient  lakes  of  the  Laurentian  basin  were  making 
their  various  records,  as  is  shown  by  the  fact  that  the  abandoned  beaches 
do  not  all  lie  in  planes  parallel  with  each  other. 

The  highest  of  the  ancient  beach  lines  about  the  north  shore  of  Lake 
Superior,  has  an  elevation  of  about  600  feet  above  the  present  lake,  as 
has  been  determined  by  A.  C.  Lawson.^     The  beaches  at  lower  levels  are 

1  "The  history  of  Xiasrara  river."  in  Sixth  Annual  Report  of  the  Commissioners  of  the 
State  Reservation  at  Niagara,  Albany,  N.  Y.,  1800,  p.  69.  Reprinted  in  Ann.  Rep.  Smith- 
sonian Institution,  1890,  pp.  231-2o7.  » 

2  "Sketch  of  the  Coastal  Topography  of  the  Xorth  Side  of  Lake  Superior,"  in  20th  Ann. 
Rep.,  Minnesota,  Geol.  and  Nat.  Hist.  Surv.,  pp.  181-289. 


STUDIES    OF    SPECIAL   LACUSTRAL   HISTORY.  101 

approximately  parallel  with  it.  Observations  on  the  amount  of  deforma- 
tion that  this  beach  has  suffered,  are  not  as  extended  as  could  be  desired, 
but  near  its  western  extension  there  is  evidence  of  a  change  of  level  of 
about  one  foot  per  mile. 

Recent  observations  by  F.  B.  Taylor  ^  in  the  region  adjacent  to  Lake 
Superior  on  the  south,  have  shown  that  ancient  beaches  may  be  clearly 
recognized  at  many  places  between  Duluth  and  Sault  Sainte  Marie.  The 
facts  recorded  by  Taylor  supplement  in  a  very  interesting  manner  the 
work  of  Lawson  on  the  northern  side  of  the  same  basin,  although  faither 
study  is  necessary  before  the  entire  history  of  the  great  predecessor  of  Lake 
Superior  can  be  written.  At  the  south,  the  highest  beach  has  an  eleva- 
tion of  from  512  to  588  feet  above  Lake  Superior,  or  from  1014  to  1190 
feet  above  the  sea. 

.Taylor  suggests  that  when  the  entire  outline  of  the  highest  Ijeach  at 
the  north  shall  have  been  traced,  it  will  he  found  that  there  were  straits 
connecting  the  Superior  basin  with  that  of  Hudson  Bay.  This  would 
imply  a  submergence  of  a  very  large  portion  of  the  North  American  con- 
tinent to  a  depth  of  over  a  thousand  feet. 

The  erosion  produced  by  the  movement  of  ice  sheets  many  hundreds 
'  of  feet  thick,  over  the  Laurentian  basin,  modified  and  sulxlued  the  pre- 
vious relief,  and  the  debris  left  when  the  ice  melted  covered  the  country 
with  a  sheet  of  superficial  deposits  to  such  a  depth  that  the  character 
of  the  underlying  hard-rock  topography  is  onl}^  occasionall}^  revealed. 
The  depth  of  these  glacial  deposits  over  great  areas,  as  in  jNIichigan 
and  Wisconsin,  is  from  one  to  two  hundred  feet,  but  is  probably  of  less 
average  thickness  in  Oliio  and  Xew  York.  All  pre-glacial  drainage  channels 
were  either  obstructed  or  obliterated  and  a  new  surface  given  to  the  land. 
The  drainage  was  tlius  rejuvenated  and  is  still  immature.  ,  The  effects  of 
glacial  plantation  and  of  glacial  deposition,  in  forming  the  basins  of  the' 
present  Laurentian  lakes,  has  been  pointed  out  in  discussing  the  origin  of 
lake  basins. 

Li  this  brief  sketch  I  have  endeavored  to  show  that  the  history  of 
the  Laurentian  basin  includes  a  study  of  the  hard-rock  topography  as  it 
existed  previous  to  the  Glacial  epoch  ;  the  disturbances  and  changes  in 
drainage  produced  by  the  ice  invasion  and  by  movements  of  elevation 
and  depression;  the  obstruction  of  the  ancient  waterways  by  glacial 
deposits  ;    and  the   origin   of  new  chainiels  of  discharge,  as  the  glaciers 

^  "A  reconnoissance  of  the  abandoned  shore  lines  of  the  soutli  coast  of  Lake  Superior," 
in  Am.  Geol.,  Vol.  13,  18!J4,  pp.  305-383.     See  also  more  recent  papers  in  the  same  journal. 


102  LAKES    OF    NOETH   AMERICA. 

passed  away,  —  all  of  these  links  in  the  complex  history  have  not  been 
completely  worked  out,  and  this  attractive  field  is  still  open  to  the  geolo- 
gist and  geographer. 

In  conclusion,  it  is  but  fair  to  state  that  while  the  history  of  the 
Laurentian  basin  outlined  above  will,  I  believe,  be  accepted  as  in  the 
main  correct  by  most  geologists  of  the  United  States,  whose  attention  has 
been  directed  to  the  subject,  it  is  widely  at  variance  with  the  conclusions 
of  at  least  two  Canadian  geologists.  Sir  J.  WilHam  Dawson  maintains,  if  I 
understand  his  hypothesis  correctly,  that  the  sea,  laden  with  icebergs,  invaded 
the  Laurentian  basin  in  Pleistocene  times,  and  that  the  moraines  and  other 
deposits  occurring  in  it  and  over  a  wide  extent  of  adjacent  country,  and 
believed  by  most  observers  to  be  of  glacial  origin,  are  shore  accumulations, 
and  that  icebergs  and  fioe-ice  played  an  important  part  in  their  formation. 

The  ancient  beaches  about  the  Laurentian  lakes,  while  considered  as 
true  shore  lines  by  Spencer,  are  thought  by  him  to  have  been  formed  at 
sea-level  during  a  time  of  continental  submergence,  and  that  the  ocean 
had  free  access  to  the  basin. 

It  may  be  that  in  these  summary  statements  I  do  injustice  to  the 
views  of  the  gentlemen  referred  to,  but  the  conclusions  indicated  are  so 
widely  at  variance  with  a  vast  body  of  consistent  evidence  gathered  by  a 
score  or  more  of  skilled  observers,  and  is  so  directly  opposed  to  my  own 
observations,  both  of  living  glaciers  and  of  the  records  of  past  giaciation, 
that  they  do  not  seem  at  present  to  be  open  to  profitable  discussion. 

A  subsidence  of  the  eastern  border  of  the  continent  during  the  later 
stages  of  the  Glacial  epoch,  or  following  its  close,  throughout  a  belt 
Avidening  from  New  York  city  northward,  and  including  the  valley  of 
Lake  Champlain,  is  well  known.  When  the  studies  leading  to  this  con- 
clusion are  extended  to  the  l^asins  of  the  Laurentian  lakes,  however,  not 
only  is  there  an  absence  of  salt-water  shells  and  other  evidences  of  marine 
occupation,  but,  seemingly,  positive  evidence  of  lacustral  condition. 

The  region  to  the  north  of  Lake  Superior  has  not  been  sufficiently 
studied  to  admit  of  an  opinion  being  reached  in  reference  to  the  questions 
just  considered,  from  the  records  there  obtained.  It  may  be  found  that 
the  highest  shore-line  in  the  Superior  basin  was  formed  by  a  water  body 
in  direct  communication  with  the  sea  to  the  north,  a.^  suggested  by 
Taylor.  Should  this  hypothesis  be  sustained,  it  would  add  an  interesting 
chapter  to  the  history  of  the  Superior  basin,  and  render  a  review  desirable 
of  the  evidence  of  a  similar  nature  in  the  eastern  portion  of  the  region 
now  drained  by  the  St.  Lawrence. 


STUDIES    OF    SPECIAL    LACUSTRAL    HISTORY.  103 

The  views  of  Dawson  and  Spencer  are  set  forth  in  the  publications 
mentioned  in  the  following  footnote,^  and  should  be  attentively  studied 
by  all  who  undertake  to  read  the  history  of  the  Laurentian  basins  from 
the  original  records  in  order  that  their  conclusions  may  be  fairly  tested. 

Lake  Agassiz. 

At  the  time  the  remarkable  changes  described  above  were  taking  place 
in  the  Laurentian  basin,  there  were  corresponding  revolutions  in  the 
geoo-raphy  of  the  region  to  the  northwest  which  now  drains  to  Lake 
Winnepeg  and  thence  through  Nelson  river  to  Hudson  bay. 

It  will  1)6  readily  seen  on  glancing  at  a  map  of  Canada,  that  if  a 
oiacier  of  the  continental  type  should  advance  southward  from  the  Hud- 
son bay  region,  the  drainage  would  be  obstructed  and  a  lake  formed  over 
the  country  of  mild  relief  surrounding  Lake  Winnepeg  and  the  Lake  of 
the  AVoods,  and  extending  southward  through  the  Ked  River  valley,  far 
into  jNIinnesota.  Such  a  lake  would  discharge  southward,  and  contribute 
its  surplus  waters  to  the  Mississippi.  Should  the  hypothetical  glacier  re- 
ferred to  advance  until  it  occupied  all  of  the  Winnepeg  basin,  the  lake 
about  its  southern  margin  would  be  obliterated,  and  there  would  be  free 
drainage  to  the  Gulf  of  Mexico.  Should  the  glacier  then  retreat  to  the 
north  of  the  divide  now  separating  the  waters  flowing  southward  to  the 
Gulf  of  ]\Iexico  from  those  flowing  northward  to  Hudson  bay,  a  lake  would 
be  born  about  the  margin  of  the  ice,  and  would  increase  northward  as  the 
ice  retreated.  When  a  channel  leading  northward  was  uncovered  and 
rendered  available  as  an  outlet  for  the  lake,  the  ponded  waters  Avould  have 
their  level  lowered  and  their  area  contracted. 

The  study  of  the  Pleistocene  records  in  the  Red  River  valley  and 
thence  northward  in  Manitol)a,  has  shown  that  changes  very  similar  to 
those  postulated  al)ove  actually  occurred. 

The  evidence  of  the  former  existence  of  a  large  lake  in  the  Red  River 
valley  was  observed  as  far  l)ack  as  1823  by  Keating,  the  geologist  of  the 
first  scientific  expedition  to  that  region.  Subsequent  contributions  to  this 
investigation   have    been    made    by    several    observers,    and    notably   by 

1  J.  W.  Dawson,  "The  Canadian  Ice  Age,"  Montreal,  18!)3  ;  J.  W.  Spencer,  "The  De- 
formation of  Iroquois  Beach  and  Birth  of  Lake  Ontario,"  in  Am.  Jour.  Sci.,  ser.  3,  vol.  40, 
1890,  pp.  44.3-451 ;  J.  W.  Spencer,  "  Deformation  of  the  Algonciuin  Beach  and  tlie  Birth  of 
Lake  Huron,"  in  Am.  Jour.  Sci.,  ser.  8,  vol.  41,  1891,  pp.  12-21;  J.  AV.  Spencer.  "Post- 
Pleistocene  Subsidence  versus  Glacial  Dams,"  in  Geol.  Soc.  Am.  Bull.,  vol.  2.  1891,  pp. 
465-474. 


104  LAKES    OF    NORTH    AMERICA. 

Gen.  G.  K.  Warren,  who  first  explained  the  origin  of  the  valley  now 
occupied  by  Lake  Traverse,  Big  Stone  lake,  and  the  Minnesota  river,  by 
showing  that  it  was  excavated  by  a  stream  flowing  to  the  Mississippi 
from  a  former  lake  to  the  north.  This  ancient  river,  whose  source  has 
long  since  been  sapped  by  northward  drainage,  has  been  named  River 
"Warren,  after  its  discoverer. 

The  great  lake  that  formerly  flooded  the  Winnepeg  basin,  and  during 
its  highest  stage  overflowed  through  River  Warren,  has  been  named  Lake 
Agassiz,  by  Warren  Upham,  in  honor  of  Louis  Agassiz.  Practically  all  ■ 
of  the  facts  and  conclusions  here  presented  concerning  the  history  of  that 
remarkal)le  lake,  have  been  made  known  through  the  long-continued  and 
skillful  investigations  of  Upham,  under  the  auspices,  at  different  times, 
of  the  geological  surveys  of  Minnesota,  the  United  States,  and  Canada,^ 
respectively. 

The  Red  River  of  the  North  rises  in  the  western  part  of  Minnesota, 
and  receives  the  tribute  of  Lake  Traverse,  situated  on  the  Minnesota- 
Dakota  boundary,  and  at  tlie  southern  limit  of  the  country  formerly 
flooded  by  Lake  iVgassiz.  From  Lake  Traverse  the  present  drainage  is 
northward  through  narrow  channels  sunken  in  the  sediments  of  the 
former  lake.  Between  the  streams  there  are  broad,  nearly  level,  inter- 
stream  spaces,  forming  typical  examples  of  new-land  areas,  on  which 
shallow  ponds  form  duiing  rainy  seasons.  About  the  borders  of  this 
broad,  level  extent  of  -prairie  lanfl,  now  transformed  into  wheat  fields, 
there  are  gravel  ridfjes  which  mark  the  surface  level  of  the  former  lake  at 
various  stages.  These  ancient  beaches  have  been  traced  northward  and 
found  to  diverge  toward  the  northeast  and  northwest  when  the  central 
area  of  the  old  lake  was  approached,  and  have  been  mapped  so  as  to  show 
approximately  the  extent  of  the  water  body  that  built  them.  By  patiently 
foUowinsf  these  ancient  shore-lines,  it  has  been  demonstrated  that  Lake 
Agassiz  covered  a  region  about  IKUKUX  square  miles  in  area.  Its 
diameter  from  north  to  south  was  Gj^ojniles,  and  from  east  to  west,  in  the 
wider  portions,  varied  from  225  to  300  miles.  It  was  the  large"^  of  ^^'*^ 
Pleistocene  lakes  of  North  America  thua,.far  discovered ,  fiiH^  f>Yppprlaa-4aTP— » 
combined  areas  of  the  present  Laurentian  lakes.  The  rim  of  its  hydro- 
graphic  basin  embraced  a  region  not  less  than  half  a  million  square  miles  in 
area.     At  the  site  of  Lake  Winnepeg  the  ancient  lake  was  GOO  feet  .deep-,  - 

1  A  report  on  these  investigations  appeared  in  the  Geol.  and  Xat.  Hist.  Survey  of  Canada, 
Ann.  Rep.,  vol.  4,  1888-9,  pp.  1-15G  E,  and  a  monograph  on  the  same  subject  is  soon  to  be 
issued  by  the  U.  S.  Geol.  Survey. 


STUDIES    OF    SPECIAL    LACUSTRAL    HISTORY.  105 

One  of  the  most  interesting  discoveries  in  connection  Avitli  the  beaches 
of  Lake  Agassiz,  is  that  they  are  no  longer  horizontal,  and  besides  do  not 
lie  in  plains  that  are  parallel  one  with  another.  The  hj^esL-Water  line- 
^h^JyUowed  northward  has  been  found  to  rise  at  the  rate  of  200  feet  in 
300  miles.  There  are  five  beaches  that  are  esjiejcially  prominent  and 
mark  a  lingering  of  the  lake  surface  at  their  respective  horizons.  The 
highest  of  the  series,  known  as  the  Herman  beach,  when  traced  northward 
from  the  southern  end  of  the  Red  River  valley,  has  been  found  to  divide 
into  several  beaches  at  different  levels;  the  vertical  intervals  l)etween  tlie 
division  increasing  northward.  The  meaning  of  this  fact  seems  to  be  that 
the  land  w^as  rising  at  the  north  at  the  time  the  l)eaches  were  formed  and 
at  the  same  time  the  surface  of  the  lake  was  lowered  by  reason  of  the 
opening  of  new  outlets. 

To  the  north  of  Lake  Winnepeg  the  higher  of  the  ancient  beaches  are 
absent  and  the  lower  ones  difficult  to  trace.  The  country  still  farther 
toward  Hudson  bay  is  low  and  does  not  present  a  barrier  that  under  any 
plausible  hypothesis  could  have  been  made  to  act  as  a  dam  to  retain  the 
waters  of  Lake  Agassiz.  What  then  could  for  a  time  have  reversed  the 
drainage  and  led  to  the  formation  of  a  lake  over  a  hundred  thousand 
square  miles  in  area  ? 

The  origin  of  Lake  Agassiz  as  explained  by  Upham,  is  in  harmony 
with  the  history  of  the  former  lakes  of  the  Laurentian  basin.  It  is  sup- 
posed  to  have  owed  its  origin  to  the  presence  of  a  vast  ice  jheet  over  the 
/Hudson  bay  region  which  dammed  the  northward  drainage  of  the  Winne- 
peg basin  and  caused  the  waters  to  rise  until  an  outlet  was  found  at  the 
south  and  River  Warren  began  to  flow.  When  the  ice  retreated,  new 
outlets  at  lower  levels  became  available  at  the  north  and  the  waters  fell, 
but  lingered  for  a  time  at  the  horizon  of  each  of  the  various  beaches  that 
have  been  referred  to,  at  lower  levels  than  the  Herman  beach. 

There  are  facts  in  connection  witli  the  ancient  floods  of  the  Laurentian 
and  Winnepeg  basins,  which  seem  to  indicate  that  the  weight  of  the  ice 
during  the  Glacial  epoch  caused  the  land  to  subside,  and  that  when  the 
ice  melted  an  upward  movement  was  initiated.  These  movements,  and 
also  the  attraction  of  the  ice  body  to  the  north  of  Lake  Agassiz,  have 
been  thought  to  ex[)lain  the  gradual  rise  of  the  beaches  when  traced 
northward. 

The  strange  transformation  that  the  Winnepeg  basin  underwent  in 
Pleistocene  times,  leads  one  to  wonder  if  in  the  region  now  drained  b}' 
Mackenzie  river,  and  occupied  in  part  by  Great  Slave  and  Great  Bear 


106  LAKES    OF    NORTH    AMERICA. 

lakes,  there  may  not  be  equally  wonderful  records  awaiting  the  coming  of 
the  patient  inquirer. 

Pleistocene  Lakes  of  the  Great  Basin. 

During  the  time  of  great  climatic  changes  that  witnessed  the  birth, 
growth,  and  decadence  of  the  great  lakes  of  the  Laurentian  and  Winnepeg 
basins,  described  above,  equally  important  fluctuations  occurred  in  the 
lakes  of  the  Arid  region.  Many  of  the  valleys  of  Utah  and  Nevada,  and 
of  adjacent  areas  both  north  and  south,  that  are  now  parched  and  desert- 
like throughout  the  year,  were  then  flooded,  and  in  some  instances  filled 
to  the  brim  so  as  to  overflow.  All  of  the  enclosed  lakes  west  of  the  Rocky 
mountains  were  then  of  greater  size  than  at  present  and  underwent  marked 
changes  in  sympathy  with  the  advance  and  retreat  of  glaciers  on  neighbor- 
ing mountains,  and  liad  their  oscillations  controlled  by  the  same  causes, 
viz.,  variations  in  precipitation,  evaporation,  and  temperature. 

Of  these  numerous  water  bodies  there  Avere  two  of  broad  extent  which 
may  be  taken  as  types  of  their  class  and  will  serve  to  give  an  epitome  of 
the  history  of  their  time.  The  two  ancient  lakes  referred  to  are  Bonne- 
ville and  Lahontani  and  are  represented  on  the  map  forming  Plate  19. 

Lake  Bonneville  was  named  by  Gilbert  in  honor  of  Captain  B.  L.  E. 
Bonneville,  U.S.A.,  who  made  a  bold  exploration  into  the  wilds  of  the 
Rocky  mountains  in  1833,  and  was  the  first  person  to  gather  reliable 
information  concerning  the  region  formerly  occupied  by  the  great  lake 
now  bearing  his  name.  The  reader  will  perhaps  liave  an  additional 
interest  in  the  folloAving  sketch,  when  he  recalls  the  "Adventures  of 
Captain  Bonneville,"  so  graphically  described  by  Washington  Irving. 

Lake  Lahontan  first  received  definite  recognition  in  the  reports  of  the 
40th  Parallel  survey  under  the  direction  of  Clarence  King,  and  was  named 
after  Baron  LaHontan,  one  of  the  early  explorers  of  the  Mississippi  valley. 
Why  LaHontan's  name  should  have  been  thus  connected  with  a  region 
more  than  a  thousand  miles  beyond  his  farthest  camp,  in  preference  to 
the  names  of  men  who  boldly  crossed  and  recrossed  the  land  referred  to 
when  it  was  a  trackless  desert  infested  with  roving  bands  of  savages,  I 
must  leave  to  others  to  explain. 

As  shown  on  the  accompanying  map,  Plate  19,  Lake  Bonneville  occu- 
pied the  basin  in  which  Great  Salt    lake  now  lies,  on  the  east  side  of  the 

1  Clarence  King,  U.  S.  Geol.  Exploration  of  the  40tli  Parallel.  Vol.  1, 1878,  pp.  490-529. 
—  G.  K.  Gilbert,  "Lake  BonneYille."  U.S.  Geol.  Surv.,  Monograph  No.  1,  1890.  —  L  C. 
Eussell,  "Lake  Lahontan."     U.  S.  Geol.  Surv..  Monograph  No.  11,  1885. 


Lakks  of  XoRTn  America. 


Plate  10. 


PLEISTOCENE    LAKES    OF    THE    GREAT    BASIN. 
This  map  is  incomplete,  as  the  entire  area  lias  not  been  studied. 


STUDIES    OF    SPECIAL    LACUSTKAL    HISTORY.  107 

Great  Basin,  while  Lake  Lahontan  flooded  a  series  of  irregular  valleys  on 
the  west  side  of  the  same  great  area  of  interior  drainage  and  is  now  repre- 
sented by  Pyramid,  Winnemucea,  Walker,  Carson,  and  IIuml)oldt  lakes, 
Nevada,  and  by  Honey  lake-,  California. 

These  two  ancient  lakes  were  contemporaries,  and,  although  differing 
in  their  histories,  bear  similar  testimony  in  reference  to  climatic  changes 
and  supplement  each  other's  records  in  a  remarkable  manner.  Their 
hydrographic  basins  joined  each  other  in  north-eastern  Nevada,  for  a 
distance  of  about  twenty-five  miles,  and  together  occupied  the  entire 
width  of  the  Great  Basin.  Lake  Bonneville  received  its  water  supply 
from  the  Wasatch  and  Uinta  mountains,  then  snow-clad  tliroughout  the 
year  and  holding  glaciers  of  the  Alpine  type  in  many  of  their  valleys. 
Several  of  the  ice  streams  on  the  precipitous  western  slope  of  the  Wasatch 
mountains  reached  nearly  to  the  ancient  lake  which  M'ashed  the  base  of 
the  range,  and  one  of  them  w^as  prolonged  for  a  short  distance  into  its 
waters.  Lake  Lahontan  derived  its  princi})al  water  sup})ly  from  the  Sierra 
Nevada,  which  formed  the  western  rim  of  its  drainage  Ijasin  for  a  distance 
of  250  miles,  and,  like  the  eastern  borders  of  the  Bonneville  basin,  Avas 
glacier-covered. 

Lake  Bonneville  at  the  time  of  its  maximum  extension  had  an  area  of 
19,750  square  miles,  and  a  hydrographic  basin  52.000  square  miles  in 
area.  The  more  irregular  water  surface  of  Lake  Lahontan.j,v,as  8. J:22 
square  miles  in  area,  and  occiipicd  the  lowest  (l('|)ressions  in  a  hydro- 
graphic  basm^contaiuing  4i).775  s(}uar&-  miles.  The  great  size  of  the 
hydrographic  basins  of  tliusc  lakes  in  comparison  with  their  extent  of 
water  surface,  is  a  noteworthy  feature.  The  ratio  of  the  extent  of  lake 
surface  to  area  of  hydrographic  basin  in  the  case  of  Lake  Bonneville  was 
as  1  to  2.6,  and  in  the  case  of  Lake  Lahontan  about  1  to  5.  The  corre- 
sponding ratios  in  the  basin  of  Lake  Superior  are  as  1  to  1.72  ;  and  for 
the  combined  Laurentian  lakes  as  1  to  3.19.  The  small  extent  of  the 
ancient  lakes  of  the  Great  Basin  in  comparison  with  the  areas  draining  to 
them,  more  especially  in  the  case  of  Lake  Lahontan,  indicates  that  the 
climate  of  their  time  was  not  markedly  humid. 

The  maximum  depth  of  Lake  Bonneville  as  recorded  by  beach  lines 
on  the  mountain  fonning  its  shores,  and  on  the  precipitous  islands  now 
rising  in  Great  Salt  lake,  was  1050  feet.  The  greatest  depth  of  Lake 
Lahontan  was  886  ieeT. 

Tlie "most  striking  difference  in  connection  with  these  two  ancient 
seas  is  in  reference  to  overflow.     The  waters  of  Lake  Bonneville  rose 


108  LAKES    OF    NORTH   AMERICA. 

until  they  found  an  outlet  and  escaped  through  a  channel  leading  north- 
ward from  Cache  valley,  in  Utah  and  Idaho,  to  Snake  river  and  thence  to 
the  Columbia.  The  outflowing  stream  at  its  source  crossed  incoherent 
alluvial  deposits  and  rapidly  cut  down  a  channel  of  discharge  to  a  depth 
of  370  feet,  thus  lowering  the  lake  by  that  amount.  During  this  episode 
in  its  history  the  lake  was  fresh,  but  at  later  stages,  when  its  surface  fell 
below  the  level  of  the  bottom  of  the  channel  of  discharge,  it  became 
saline.  The  water  supply  of  Lake  Lahontan  was  less  abundant  and  it 
never  rose  so  as  to  find  an  outlet.  Its  waters  were  perhaps  brackish 
during  its  higher  stages,  and  became  saline  and  alkaline  as  concentration 
progressed. 

Each  of  these  lakes  had  two  high-water  stages,  separated  by  a  time  of 
low  water  and  probably  of  complete  desiccation.  The  second  high-water 
stage  in  each  instance  was  the  more  marked  of  the  two.  These  fluctua- 
tions are  indicated  in  the  following  diagram  of  the  rise  and  fall  of  Lake 
Lahontan. 

Each  lake  spread  out  two  sheets  of  fine,  evenly-laminated  clays,  sepa- 


FiG.  g.  _  Diagram  showing  the  Rise  ajvd  Fall  of  L.Uve  Lahoxt.oc. 

•rated,  at  least  about  their  borders,  by  deposits  of  coarse  gravel  and  sand 
washed  in  from  the  adjacent  slopes  during  the  inter-lacustral  time  of  low 
water. 

There  are  many  reasons  for  concluding  that  the  two  high-water  stages 
recorded  by  beach  lines  and  by  sedimentary  deposits  in  the  basins  of  lakes 
Bonneville  and  Lahontan,  correspond  in  time  with  two  of  the  periods  of 
glaciation  recorded  in  the  Laurentian  basin.  Two  periods  of  marked 
advance  separated  by  a  time  of  retreat,  are  also  indicated  by  the  glacial 
records  in  the  canons  of  the  Sierra  Nevada. 

The  waters  of  both  Bonneville  and  Lahontan  underwent  many  minor 
fluctuations  of  level  as  is  the  rule  with  all  enclosed  lakes.  The  terraces, 
embankments,  deltas,  etc.,  constructed  about  the  shores  of  Lake  Bonne- 
ville are  on  a  grander  scale  than  in  the  basin  of  its  companion  lake,  for 


STUDIES    OF    SPECIAL    LACUSTRAL   HISTORY.  109 

the  reason  that  it  was  the  hirger  of  the  two  water  bodies  and  had  a  more 
regular  outline,  thus  giving  the  wind  a  better  opportunity  to  act  on  its 
waters,  and  also  because  it  Avas  held  at  a  definite  level  for  a  long  period, 
or  rose  to  the  same  horizon  at  various  times,  on  account  of  its  having  an 
outlet. 

The  highest  water  line  about  Lake  Bonneville,  named  the  "  Bonneville 
beach,"  is  conspicuous  not  so  much  on  account  of  its  strength  as  for  the 
reason  that  it  marks  the  dividing  line  between  rain  sculpture  on  the 
higher  portions  of  the  bordering  mountains  and  the  characteristic  topogra- 
phy due  to  the  work  of  waves  and  currents  on  their  lower  slopes.  The 
channel  of  discharge  was  lowered  until  a  sill  of  resistant  limestone  was 
reached  which  determined  the  horizon  of  the  strongest  and  best  developed 
terraces  and  embankments  in  the  basin.  A  well  defined  beach  at  this 
horizon  is  known  as  the  "  Provo  beach,"  the  name  being  derived  from  the 
town  of  Provo,  Utah,  which  stands  on  a  broad  delta  formed  by  the  sedi- 
ment of  Provo  river,  when  the  lake  stood  at  the  horizon  of  its  lowest 
point  of  discharge.  The  wave-built  structures  marking  the  Provo  stage 
are  on  a  magnificent  scale  and  are  still  almost  as  fresh  in  appearance  and 
perfect  in  form  as  if  abandoned  by  the  waves  but  yesterday.  In  the 
Lahontan.  basin  the  shore  topography  was  never  strongly  pronounced. 
Fluctuations  of  level  were  not  controlled  by  an  outlet,  and  the  numerous 
islands  and  headlands  diminished  the  influence  of  the  wind  and  checked 
the  action  of  waves  and  currents. 

The  chemical  histories  of  lakes  Bonneville  and  Lahontan  are  fully  as 
instructive  and  of  as  great  interest  as  their  physical  changes.  In  this 
connection,  the  basin  of  Lake  Lahontan  has  been  found  to  exceed  its 
companion  in  the  completeness  of  its  records.  The  escape  of  the  waters 
of  Lake  Bonneville  insured  its  freshness  during  a  part  of  its  history.  The 
absence  of  an  outlet  for  the  waters  of  Lake  Lahontan  led  to  a  high  degree 
of  concentration. 

When  lake  waters  are  concentrated  by  evaporation  the  first  substance 
to  be  precipitated,  as  previously  described,  is  calcium  carbonate.  About 
the  shores  of  Lake  Bonneville  there  are  in  favorable  localities,  consider- 
able deposits  of  this  substance  in  the  form  of  coral-like  incrustations 
knoAvn  as  calcareous  tufa.  It  appears  on  rocky  points  and  forms  a  cement 
for  gravel  and  sand  on  the  outer  borders  of  some  of  the  terraces,  but  is 
insignificant  in  amount  and  simple  in  character,  when  compared  with 
the  truly  immense  accumulations  of  a  similar  nature  in  the  Lahontan 
basin. 


110  LAKES    OF    NORTH    AMERICA. 

The  precipitation  of  calcium  carbonate  from  lake  waters  takes  place 
principally  in  two  ways ;  it  may  separate  in  the  open  lake  and  fall  to  the 
bottom  in  a  finely  divided  state  and  become  mingled  with  mechanical 
sediments  so  as  to  form  marls,  or  it  may  be  precipitated  where  solid 
rocks  occur  and  cover  them  with  a  dense  incrustation.  The  ability  of 
ordinary  surface  waters  to  dissolve  calcium  carbonate,  depends  mainly  on 
the  carbonic  acid  gas  they  liold  in  solution.  Lake  waters  lose  tlieir  dis- 
solved gases  most  rapidly  where  tliey  form  breakers  along  the  shore,  as  in 
such  instances  they  are  most  thoroughly  aerated.  For  this  reason,  the 
boldest  headlands  are  apt  to  receive  tlie  heaviest  deposits  of  tufa  Avhen  the 
waters  dashed  against  them  became  concentrated.  It  is  at  such  localities 
that  the  principal  deposits  of  tufa  in  the  Bonneville  basin  occur.  It 
happens  also  that  calcium  carbonate  has  a  tendency  to  accumulate  about 
solid  l)odies,  not  only  because  they  afford  a  stable  su[)port,  but  for  the 
additional  reason  that  points  and  angles  induce  crystallization.  Calcareous 
tufa  was  deposited  in  vast  quantities  about  the  shores  of  Lake  Lahontan 
wherever  there  were  rocky  slopes  and  in  increasing  abundance  from  an 
horizon  high  up  on  its  borders  down  to  the  deepest  point  now  exposed. 
The  fluctuations  of  level  in  Lake  Bonneville  were  recorded  principally  by 
beaches  and  embankments  of  mechanical  origin  ;  similar  changes  in  Lake 
Lahontan  are  made  known  by  tufa  deposits  of  chemical  origin. 

The  tufa  of  the  Lah(mtan  basin  presents  three  main  varieties,  each  of 
which  is  composed  of  concentric  layers  as  is  shown  in  Plate  21.  The 
smaller  divisions  seem  to  indicate  minor  changes  in  the  chemistry,  and 
perhaps  also  fluctuations  in  the  temperature,  of  the  water  from  which  they 
were  precipitated.  The  three  principal  varieties  have  been  named  in  the 
order  of  their  formation,  Lithoid,  Thinolitic,  and  Dendritic  tufa.  Lithoid 
tufa  is  a  compact  stony  substance  with  a  granular  texture  ;  Dendritic  tufa 
has  an  open  structure  and  resembles  a  mass  of  branching  twigs  turned  to 
stone ;  and  Thinolitic  tufa,  shown  in  Plate  22,  is  composed  of  Avell 
defined  crystals  to  Avhich  the  name  Thinolite  was  given  b}-  Clarence 
King.  The  comjjosition  of  each  of  these  varieties  is  the  same.  They  are 
composed  of  calcium  carbonate  with  usuall}'-  some  slight  amount  of  im- 
purities. Their  wide  variation  in  structure  and  general  appearance,  is 
due  to  differences  in  the  condition  of  the  lake  waters  at  the  time  of 
their  formation. 

About  Pyramid  lake.  Avhere  the  Lahontan  tufas  are  usually  well  dis- 
played, the  first  or  Lithoid  variety  reaches  a  height  of  500  feet,  the  Thino- 
litic  110    feet,  and   the   third   or  Dendritic  variety,  320  feet  above  the 


Lakes  of  North  America. 


Plate  20. 


_;  A   TOWERS    ON    THE    SH. 


LAKE,    NEVADA. 


STUDIES    OF    SPECIAL    LACUSTilAL    HISTORY.  Ill 

surface  of  the  present  lake.     The  rehition  of  the  tufa  deposits  and  the 
terraces  with  which  they  are  associated,  are  shown  in  the  following  diagram. 


Lahontan  Beach 530  feet. 

Lithoid  Terrace 5(X»     " 


Dendritic  Terrace 320     " 

^_.     Thinolitic  Terrace 110     " 

Surface  of  Pyramid  Lake,  1882    .    .        0     " 


^^ 


Fig.  9.  —  DiAGRAjr  shovtixg  the  relation  of  the  Terraces  of  Lake  Lahontan 
TO  Pyramid  Lake. 

The  Lithoid  tufa  near  its  upper  limit  is  seldom  over  eight  or  ten 
inches  thick,  but  increases  to  ten  or  twelve  feet  on  the  lower  slopes.  The 
Thinolite  is  usually  from  six  to  twelve  feet  thick.  The  Dendritic  variety 
is  the  heaviest  of  all  and  frequently  appears  on  steep  slopes  in  imbricated 
layers  from  fifty  to  sixty  feet  thick.  In  some  favorable  locality  the  entire 
tufa  deposits  have  a  thickness  of  at  least  eighty  feet,  and  in  rare  places 
near  the  surface  of  Pyramid  lake  and  partially  concealed  by  its  waters, 
there  is  evidence  that  these  deposits  are  still  more  massive.  The  total 
amount  of  calcium  carbonate  deposited  from  the  ancient  lake  can  only  be 
estimated  in  millicjns,  if  not  billions  of  tons. 

Every  island  and  rocky  crag  that  rose  in  Lake  Lahontan  l^ecame  a  cen- 
ter of  accumulation  for  tufa  deposits  and  was  transformed  into  strange  and 
frequently  fantastic  shapes  by  the  material  precipitated  upon  it.  Noav 
that  the  waters  of  the  ancient  sea  have  disappeared,  these  structures  stand 
in  the  desert  valleys  like  the  crumbling  ruins  of  towers,  castles,  domes,  and 
various  other  shapes,  in  keeping  with  the  desolation  surrounding  them. 
The  finest  examples  of  these  water-built  structures,  some  of  them  a  hun- 
dred feet  or  more  in  height,  occur  about  the  border  of  Pyramid  and 
Winnemucca  lakes  (Plate  20),  or  rising  from  their  bottoms  and  still 
Avholly  or  in  part  sul)inerged.  The  islands  in  Pyramid  lake  are  sheathed 
from  base  to  summit  with  these  deposits  and  their  precipitous  sides  given 
a  convex  outline,  owing  especially  to  the  vast  deposits  of  Dendritic  tufa, 
which  was  pi'ecipitated  most  abundantly  midway  up  the  slopes.  The 
most  remarkable  of  these  islands,  and  the  one  from  which  tlie  lake  derives 
its  name,  is  shown  in  the  sketch  forming  Plate  23.  When  the  tufa  towers 
and  castle-like  piles  are  broken,  the  concentric  layers  of  which  they  are 
composed  are  revealed  and  fill  one  with  wonder  at  the  vast  amount  of 
material  they  contain,  as  well  as  attract  the  eye  on  account  of  the  delicacy 


112  LAKES    OF    NORTH    AMERICA. 

and  beauty  of  their  structure.  Nowhere  else  in  this  country,  and  so  far 
as  rejDorted,  nowhere  else  in  the  world,  are  I'ocks  formed  of  precipitates 
from  lake  waters  so  magnificently  disj)layed  as  in  the  desert  valleys  of 
Nevada. 

The  fascination  of  the  weird  and  frequently  Avonderfully  impressive 
scenery  of  the  region  formerly  submerged  beneath  the  waters  of  Lake 
Lahontan,  is  enhanced,  at  least  to  the  geologist,  by  the  fact  that  there  is 
yet  an  unsolved  mystery  connected  with  the  tufa  deposits  that  start  out 
as  strange,  gigantic  forms  from  the  desert  haze,  as  one  slowly  traverses 
those  bitter,  alkaline  lands. 

It  is  believed  that  we  understand  how  the  more  compact  and  stone- 
like variety  of  tufa  was  deposited,  since  similar  accumulations  are  formed 
where  waters  saturated  with  calcium  carbonate  deposit  that  salt  on  account 
of  the  loss  of  carbonic  acid.  The  Dendritic  tufa  may  also  have  been  pre- 
cipitated in  a  similar  manner,  or  perhaps  through  the  agency  of  low  forms 
of  plant  life.  The  mode  of  origin  of  the  tufa  with  well-defined  crystals, 
however,  is  still  unknown,  although  both  geologists  and  chemists  have 
sought  diligently  to  discover  the  secret  of  its  formation.  The  open  cellu- 
lar structure  of  the  crystals,  as  well  as  their  forms,  suggest  that  they  are 
pseudomorphs,  that  is,  having  a  false  form,  or  a  form  not  assumed  by  cal- 
cium carbonate  on  crystallizing,  but  resulting  from  the  alteration  or 
replacement  of  some  other  mineral.  This  suggestion  only  removes  the 
difficulty  one  step  farther,  however,  since  the  nature  of  the  original  min- 
eral is  still  unknown.  A  more  definite  statement  of  this  jDroblem  may  be 
found  in  a  special  report  on  Thinolite,  by  E.  S.  Dana,  who  has  put  the 
matter  in  a  clearer  light  than  had  previously'  been  done.^ 

One  of  the  most  remarkable  facts  in  connection  with  the  history  of  the 
Lahontan  basin,  is  thjit  the  present  lakes  within  it,  which  might  be  sup- 
posed to  be  remnants  of  the  ancient  water-bod}-  left  by  incomplete  evap- 
oration, and  therefore  intensely  saline,  are  in  reality  scarcely  more  than 
brackish.  As  shown  in  the  table  of  analyses  of  saline  lakes  given  on 
jjage  72,  Pyramid,  Winnemucca,  and  Walker  lakes,  the  representative 
water  bodies  now  existing  in  the  Lahontan  basin,  carry  only  a  small  frac- 
tion of  one  per  cent  of  saline  matter  in  solution.  We  know  that  Lake 
Lahontan  did  not  overflow.  All  of  the  saline  matter  carried  into  it, 
therefore,  must  still  be  retained  in  its  basin.  The  vast  quantity  of  vari- 
ous salts,  and  especially  of  sodium  chloride,  sodium  sulphate,  and  sodium 

1  "  Crystallographic  Study  of  the  Thiuolite  of  Lake  Lahontan.""  BuUethi  No.  12,  U.  S. 
Geol.  Survey. 


^      Q 


O 


STUDIES    OF    SPECIAL    LACUSTRAL    HISTORY.  113 

carbonate  thus  concentrated,  is  indicated  hy  the  Aveight  of  the  calcareous 
tufa  lining  the  basin.  In  orcUnary  river  waters,  as  already  shown,  the 
calcium  carbonate  is  about  the  same  as  the  amount  of  all  other  salts  in 
solution.  It  follows,  therefore,  that  the  more  soluble  salts  contributed  to 
Lake  Lahontaii  must  have  Ijeen  equal  in  weight  to  the  tufa  deposits  just 
described.  Such  a  vast  quantity  of  saline  matter,  if  contained  in  the 
present  lakes,  would  make  them  concentrated  brines.  The  question  is, 
what  has  become  of  the  more  soluble  salts  contributed  to  the  waters  of  the 
ancient  sea  ? 

A  lake  may  occasionally  evaporate  to  dryness,  or  exist  as  a  playa  lake 
for  a  long  period,  that  is,  expanding  during  rainy  seasons  and  becoming 
desiccated  either  during  dry  seasons,  or  occasionally  in  years  of  unusual 
aridity.  Under  such  conditions  its  contained  salts  would  be  precipitated 
and  become  buried  or  absorbed  by  mechanical  sediments,  so  that  when 
a  change  of  climate  permitted  the  existence  of  a  perennial  lake  in  the 
same  basin,  it  would  be  fresh,  or  essentially  so.  This  is  what  seems  to 
have  occurred  in  the  Lahontan  basin.  The  old  lake  was  probably  evapor- 
ated to  dryness  and  the  precipitated  salts  buried  beneath  playa  clays,  and 
when  a  change  to  slightly  more  humid  conditions  permitted  of  the  Ijirth 
of  the  present  lakes,  a  new  cycle  was  Ijegun. 

From  analyses  of  the  waters  flowing  into  the  present  lake  of  the 
Lahontan  basin,  it  has  been  estimated  that  under  existing  conditions  they 
would  acquire  their  present  degree  of  salinity  in  about  300  years.  It 
seems  to  follow  from  this  study  that  during  a  long  term  of  years,  ending 
about  300  years  ago,  the  climate  of  Nevada  was  so  intensely  arid  that  no 
perennial  lakes  could  exist  within  her  borders. 

An  account  of  the  physical  and  chemical  histories  of  the  ancient  lakes 
of  Utah  and  Nevada  should  be  followed  by  a  description  of  the  plants  and 
animals  that  found  a  home  on  their  shores,  but  unfortunately  our  informa- 
tion in  this  connection  is  vague. 

The  sediments  of  lakes  Bonneville  and  Lahontan,  unlike  many  other 
lake-beds,  are  extremely  poor  in  vegetable  fossils.  As  the  conditions  for 
the  preservation  of  such  remains  were  favorable,  and  as  an  extended 
search  has  failed  to  unearth  so  much  as  a  single  leaf  or  a  single  water- 
logged tree-trunk  from  their  sediments,  it  may  reasonably  be  concluded 
that  their  shores  were  not  forested,  and  were  probably  even  more  barren 
and  desolate  than  at  the  present  day.  This  result  cannot  be  considered 
as  surprising  in  view  of  the  great  fluctuation  of  climate  that  the  Great 
Basin  experienced  in  Pleistocene  times. 


114  LAKES    OF    NORTH    AMERICA. 

Of  the  remains  of  vertebrates,  the  bones  of  the  mastodon  or  mammoth, 
and  of  the  ox,  camel,  and  horse  have  been  found  in  the  sediments  of  Lake 
Lahontan,  together  with  a  single  undetermined  fish.  The  bones  of  a 
musk-ox  were  obtained  near  Salt  Lake  City  under  such  conditions  that  it 
is  believed  they  were  buried  in  the  upper  strata  of  the  Bonneville  sedi- 
ments. The  basins  of  contemporaneous  lakes  in  Oregon,  have  yielded 
vertebrate  fossils  more  abundantly,  but  concerning  these  there  are  differ- 
ences of  opinion  as  to  their  age.  It  is  probable  that  some  of  them  at  least, 
and  perhaps  the  larger  portion,  were  washed  out  of  older  deposits  and 
accumulated  in  the  basin  where  they  are  now  found. 

In  the  sediments  of  both  Bonneville  and  Lahontan  there  are  many 
species  of  fresh-water  shells,  but  these  are  usually  small  individuals,  and 
appear  to  have  lived  under  uncongenial  conditions. 

The  remains  of  animal  life  do  not  seem  to  point  to  any  very  definite 
conclusion.  We  are  led  to  believe  from  all  of  the  evidence  available, 
however,  that  the  climate  of  the  lake  period  was  cold  and  changeable, 
and  consequently  uncongenial  to  either  plant  or  animal  life.  The  inter- 
lacustral  epoch  was  probably  a  time  of  high  temperature  and  aridity. 
The  large  animals  whose  bones  have  been  discovered  may  have  been 
forced  to  migrate  owing  to  wide-reaching  climatic  changes,  and  were  per- 
haps only  temporary  visitors  to  the  region  where  they  succumbed  to  ad- 
verse conditions. 

The  mastodon  and  mammoth  roamed  over  nearly  the  whole  of  North 
America  during  Pleistocene  times,  but  have  since  become  extinct.  The 
camel  is  no  longer  found  on  this  continent,  and  the  horse  was  extinct 
before  the  coming  of  the  white  man.  The  musk-ox  is  now  found  only 
far  to  the  north.  The  extinction  of  some  of  these  large  animals,  and 
the  scattering  of  others  to  distant  regions,  suggests  the  lapse  of  a  long 
period  of  time  since  they  lived  together  where  their  remains  are  now 
found,  and  also  points  to  great  changes  in  climatic  and  other  elements  of 
their  environment. 

Of  the  presence  of  man  on  the  shores  of  lakes  Bonneville  and  Lahon- 
ton  the  records  are  silent. 

Lakes  of  the  Remote  Past. 

The  presence  of  the  bones  of  large  animals  in  the  sediments  of  lakes 
Bonneville  and  Lahontan  naturally  leads  one  to  look  farther  back  in 
the  earth's    history,  to  the  deposits  of    other    lakes   from  which    a  vast 


STUDIES    OF    SPECIAL    LACUSTRAL    HISTORY.  115 

menagerie   of  strange   and  frequently  gigantic   forms    have   been  made 
known  by  the  hxbors  of  American  paleontologists. 

Immediately  preceding  the  "  Great  Geological  Winter,"  as  the  Glacial 
epoch  has  been  termed,  when  half  of  the  North  American  continent  was 
sheathed  in  ice,  there  was  a  period  of  genial  climate  when  vegetation,  as 
varied  and  beautiful  as  that  of  the  Mississippi  valley  to-day,  extended  far 
north  and  reached  the  vicinity  of  the  pole  itself.  During  different  epochs 
in  this  geological  summer,  known  as  the  Tertiary  period,  vast  fresh-water 
lakes  existed  in  the  Cordilleran  region,  several  of  which  were  far  more 
extensive  than  any  lakes  now  known.  In  some  of  these  vast  inland  seas 
several  thousand  feet  of  sediments  were  laid  down.  In  these  deposits 
we  lind  in  abundance  the  impressions  of  leaves  that  were  blown  from  the 
land,  or  washed  in  by  tributary  streams,  and  the  bones  of  many  large 
mammals,  whose  homes  were  along  the  lake  shores  and  on  neighboring 
forest-covered  hills. 

All  trace  of 'the  shore  topography  of  the  Tertiary  lakes  has  disap- 
peared, and  in  many  instances  the  beds  of  sand,  clay,  and  volcanic  dust 
deposited  over  their  bottoms  have  been  upheaved  into  mountain  ranges, 
and  deeply  dissected  by  erosion.  Their  histories  can  only  be  deciphered 
from  the  records  in  their  sediments.  Their  story  deals  largely  with  the 
structure,  habits,  and  development  of  vertebrate  animals,  and  must  be  left 
to  those  skilled  in  that  branch  of  study. 

Beyond  the  Tertiary  period,  and  so  remote  from  our  own  time  that 
humble  forms  of  mammalian  life  had  only  just  appeared  on  the  earth, 
were  the  Jurassic  and  Triassic  periods.  In  this  Mesozoic  time,  or  middle 
age  of  the  earth,  lakes  also  existed,  and  in  their  sediments  the  skeletons  of 
another  striking  and  grotesque  assemblage  of  strange  forms  were  pre- 
served. The  magic  wand  of  modern  science  has  brought  forth  from  these 
long-silent  tombs  a  wonderful  procession  of  gigantic  reptiles,  the  like  of 
which  has  not  since  existed  on  the  earth. 

Still  more  remote  were  the  lakes  and  swamps  of  the  Carboniferous 
period.  The  oldest  records  of  air-breathing  vertebrates  yet  discovered  are 
the  bones  of  reptiles  found  by  Dawson  in  hollow-tree  trunks  that  stood  in 
the  fresh-water  swamps  of  Nova  Scotia  during  the  time  our  continent  was 
green  with  the  ferns  and  club-mosses  of  the  Coal  period.  With  these  bones 
are  mingled  the  shells  of  land-snails,  the  earliest  of  their  class  yet  found. 

In  deposits  of  cannel  coal  formed  in  fresh-water  })onds  in  the  great 
coal  swam[)s  of  Ohio,  Newbery  discovered  a  large  number  of  species  of 
fishes  and  amphibians,  in  a  beautiful  state  of  preservation. 


116  LAKES    OF    NORTH   AMERICA. 

Farther  back  still  in  the  records  of  the  past  are  other  fragments  of  the 
earth's  history  sealed  up  and  preserved  in  lake  deposits.  The  heavy  beds 
of  sandstone  comjDOsing  the  Catskill  mountains,  and  forming  a  part  of  the 
Devonian  system,  contain  shells  which  resemble  the  covering  of  fresh- 
water mollusks,  and  may  indicate  that  the  sands  in  which  they  were 
buried  are  of  lacustral  origin.  Here  the  evidence  of  terrestrial  lakes 
seems  to  end.  "What  inland  water  bodies  existed  in  remote  Silurian, 
Cambrian,  and  Algonkian  times,  remains  to  be  discovered. 


Lakes  of  Xoutm  America. 


Plate 


A   CHARACTERISTIC    SPECIMEN    OF   THINOLITE. 


SUPPLEMEJSTT. 


The  advance  made  in  the  study  and  in  the  interpretation  of  the  meaning 
of  topographic  forms,  has  been  so  great,  especially  in  America,  during  the 
present  decade,  that  I  am  sure  the  reader  will  be  interested  in  the  writings  of 
those  who  have  made  this  important  departure  from  old  methods.  The  recog- 
nition that  lakes  are  transient  features  of  the  ever-changing  earth's  surface  and 
come  and  go  during  cycles  of  topographic  development,  was  first  clearly  set 
forth  in  a  brief  paper  by  W.  M.  Davis,^  which  is  here  reproduced. 

The  Classificatiox  of  Lakes. 

Several  years  ago  I  presented  to  the  Boston  Society  of  Xatural  History  a 
paper  on  the  classification  of  lake-basins,  in  which  the  many  v  irieties  of  lakes 
were  grouped  under  three  heads,  according  -as  they  were  made  by  constructive, 
destructive,  or  obstructive  processes.  The  first  heading  included  lakes  made 
by  mountain-folding  and  other  displacements  ;  the  second  consisted  chiefly  of 
basins  of  glacial  erosion ;  the  third  contained  the  greatest  number  of  varieties, 
such  as  lakes  held  by  lava,  ice,  and  drift  barriers,  delta  and  ox-bow  lakes,  and 
some  others.  The  classification  proved  satisfactory,  in  so  far  as  it  suggested 
a  systematic  arrangement  of  all  kinds  of  lakes  that  have  been  described ;  but 
it  now  appears  unsatisfactory,  inasmuch  as  its  arrangement  is  artificial,  Avith- 
out  reference  to  the  natural  relations  of  lakes  to  the  development  of  the  drain- 
age systems  of  A^hich  they  are  a  part.  A  more  natural  classification  is  here 
presented  in  outline. 

When  a  new  land  rises  from  below  the  sea,  or  when  an  old  land  is  seized 
by  active  mountain-growth,  new  rivers  establish  themselves  upon  the  surface 
in  accordance  with  the  slopes  presented,  and  at  once  set  to  work  at  their  long 
task  of  carrying  away  all  of  the  mass  that  stands  above  sea-level.  At  first, 
before  the  water-ways  are  well  cut,  the  drainage  is  commonly  imperfect : 
lakes  stand  in  the  undrained  depressions.  Such  lakes  are  the  manifest  signs 
of  immaturity  in  the  life  of  their  drainage  system.  We  see  examples  of  them 
on  new  land  in  southern  Florida ;  and  on  a  region  lately  and  actively  dis- 
turbed in  southern  Oregon,  among  the  blocks  of  faulted  country  described  by 
Eussell.  But  as  time  passes,  the  streams  fill  up  the  basins  and  cut  down  the 
barriers,  and  the  lakes  disappear.     A  mature  river  of  uninterrupted  develop- 

1  Science,  vol.  10,  1887,  pp.  142,  143. 


118  SUPPLEMENT. 

ment  has  no  such  immature  features  remaining.  The  life  of  most  rivers  is, 
however,  so  long,  that  few,  if  any,  complete  their  original  tasks  undisturbed. 
Later  mountain-growth  may  repeatedly  obstruct  their  flow ;  lakes  appear 
again,  and  the  river  is  rejuvenated.  Lake  Lucerne  is  thus,  as  Heim  has  shown, 
a  sign  of  local  rejuvenation  in  the  generally  mature  Reuss.  The  head  waters 
of  the  Missouri  have  lately  advanced  from  such  rejuvenation;  visitors  to  the 
National  Park  may  see  that  the  Yellowstone  has  just  regained  its  former 
steady  flow  by  cutting  down  a  gate  through  the  mountains  above  Livingston, 
and  so  draining  the  lake  that  not  long  ago  stood  for  a  time  in  Paradise  valley. 
The  absence  of  lakes  in  the  Alleghany  mountains,  that  was  a  matter  of  sur- 
prise to  Lyell,  does  not  indicate  any  peculiarity  in  tlie  growth  of  the  moun- 
tains, but  only  that  they  and  their  drainage  system  are  very  old. 

The  disappearance  of  original  and  mountain-made  lakes  is  therefore  a  sign 
of  advancing  development  in  a  river.  Conversely,  the  formation  of  small 
shallow  lakes  of  quite  another  character  marks  adolescence  and  middle  life. 
During  adolescence,  when  the  head-water  streams  are  increasing  in  number 
and  size,  and  making  rapid  conquest  of  land-waste,  the  lower  trunk-stream 
may  be  overloaded  with  silt,  and  build  up  its  flood-plain  so  fast  that  its  smaller 
tributaries  cannot  keep  pace  with  it  :  so  the  lakes  are  formed  on  either  side  of 
the  Eed  River  of  Louisiana,  arranged  like  leaves  on  a  stem;  the  lower  Danube 
seems  to  present  a  similar  case.  The  flood-plains  of  well-matured  streams 
have  so  gentle  a  slope  that  their  channels  meander  through  great  curves. 
When  a  meander  is  abandoned  for  a  cut-off,  it  remains  for  a  time  as  a  cres- 
centic  lake.  When  rivers  get  on  so  far  as  to  form  large  deltas,  lakes  often 
collect  in  the  areas  of  less  sedimentation  between  the  divaricating  channels. 
Deltas  that  are  built  on  land  where  the  descent  of  a  stream  is  suddenly 
lessened  and  its  enclosing  valley-slopes  disappear,  do  not  often  hold  lakes  on 
their  own  surface  ;  for  their  slope  is,  although  gentle,  rather  too  steep  for  that : 
but  they  commonly  enough  form  a  lake  by  ol)structing  the  .stream  in  whose 
valley  they  are  built.  Tulare  Lake  in  southern  California  has  been  explained 
by  Whitney  in  this  way. 

The  contest  for  drainage  area  that  goes  on  between  streams  heading  on  the 
opposite  slopes  of  a  divide  sometimes  produces  little  lakes.  The  victorious 
stream  forces  the  divide  to  migrate  slowly  away  from  its  steeper  slope,  and 
the  stream  that  is  thus  robbed  of  its  head  waters  may  have  its  diminished 
volume  clogged  by  the  fan-deltas  of  side-branches  farther  down  its  valley. 
Heim  has  explained  the  lakes  of  the  Engadine  in  this  way.  The  Maira  has, 
like  an  Italian  brigand,  plundered  the  Inn  of  two  or  more  of  its  upper  streams 
and  the  Inn  is  consequently  ponded  back  at  San  Moritz  and  Silvaplana.  On 
the  other  hand,  the  victorious  stream  may  by  this  sort  of  conquest  so  greatly 
enlarge  its  volume,  and  thereby  so  quickly  cut  down  its  upper  valley,  that  its 
lower  course  will  be  flooded  with  gravel  and  sand,  and  its  weaker  side-streams 


SUPPLEMENT.  119 

ponded  back.  No  cases  of  this  kind  are  described,  to  my  knowledge,  but  they 
will  very  likely  be  found ;  or  at  least  we  may  expect  them  to  appear  when  the 
northern  branches  of  the  Indus  cut  their  way  backwards  through  the  inner- 
most range  of  the  Himalaya,  and  gain  possession  of  the  drainage  of  the 
plateaus  beyond ;  for  then,  as  the  high-level  waters  find  a  steep  outlet  to  a 
low-level  discharge,  they  will  carve  out  canons  the  like  of  which  even  Button 
has  not  seen,  and  the  heavy  wash  of  waste  will  shut  in  lakes  in  lateral  ravines 
at  many  points  along  the  lower  valleys. 

In  its  old  age,  a  river  settles  down  to  a  quiet,  easy,  steady-going  existence. 
It  has  overcome  the  difficulties  of  its  youth,  it  has  corrected  the  defects  that 
arose  from  a  period  of  too  rapid  growth,  it  has  adjusted  the  contentions  along 
the  boundary-lines  of  its  several  members,  and  has  established  peaceful  rela- 
tions with  its  neighbors  :  its  lakes  disappear,  and  it  flows  along  channels  that 
meet  no  ascending  slope  on  their  way  to  the  sea. 

Certain  accidents  to  which  rivers  are  subject  are  responsible  for  many 
lakes.  Accidents  of  the  hot  kind,  as  they  may  be  called  for  elementary  dis- 
tinction, are  seen  in  lava-flows,  which  build  great  dams  across  valleys  :  the 
marshes  around  the  edge  of  the  Snake  river  lava-sheets  seem  to  be  lakes  of 
this  sort,  verging  on  extinction  :  crater  lakes  are  associated  with  other  forms 
of  eruption.  Accidents  of  the  cold  kind  are  the  glacial  invasions:  we  are 
perhaps  disposed  to  overrate  the  general  importance  of  these  in  the  long  his- 
tory of  the  world,  because  the  last  one  was  so  recent,  and  has  left  its  numerous 
traces  so  near  the  centers  of  our  civilization  ;  but  the  temporary  importance  of 
the  last  glacial  accident  in  explaining  our  home  geography  and  our  human 
history  can  hardly  be  exaggerated.  During  the  presence  of  the  ice,  especially 
during  its  retreat,  short-lived  lakes  were  common  about  its  margin.  We  owe 
many  prairies  to  such  lakes.  The  rivers  running  from  the  ice-front,  overloaded 
with  sand  and  silt,  fllled  up  their  valleys  and  ponded  back  their  non-giacial 
side-streams  ;  their  shore-lines  have  been  briefly  described  in  Ohio  and  Wis- 
consin, but  the  lakes  themselves  Avere  drained  when  their  flood-plain  barriers 
were  terraced  ;  they  form  an  extinct  species,  closely  allied  to  the  existing 
Danube  and  Red  River  type.  As  the  ice-sheet  melts  away,  it  discloses  a  sur- 
face on  which  the  drift  has  been  so  irregularly  accumulated  that  the  new 
drainage  is  everywhere  embarrassed,  and  lakes  are  for  a  time  very  numerous. 
Moreover,  the  erosion  accomplished  by  the  ice,  especially  near  the  centers  of 
glaciation,  must  l)e  held  responsible  for  many,  though  by  no  means  for  most, 
of  these  lakes.  Canada  is  the  American  type,  and  Finland  the  European,  of 
land-surface  in  this  condition.  The  drainage  is  seen  to  be  very  immature,  but 
the  imuuiturity  is  not  at  all  of  the  kind  that  characterized  the  first  settlement 
of  rivers  on  these  old  lands  :  it  is  a  case,  not  of  rejuvenation,  but  of  regenera- 
tion ;  the  icy  bajitism  of  the  lands  has  converted  their  streams  to  a  new  spirit 
of  lacustrine   hesitation   unknown   before.     We  cannot,  however,  expect  the 


120  SUPPLEMENT. 

conversion  to  last  very  long  :  there  is  already  apparent  a  backsliding  to  the 
earlier  faith  of  steady  flow,  to  which  undisturbed  rivers  adhere  closely  through- 
out their  lives. 

Water-surface  is,  for  the  needs  of  man,  so  unlike  land-surface,  that  it  is 
natural  enough  to  include  all  water-basins  under  the  single  geographic  term, 
'  lakes.'  Wherever  they  occur,  —  in  narrow  mountain-valleys  or  on  broad,  level 
plains ;  on  divides  or  on  deltas  ;  in  solid  rock  or  in  alluvium,  —  they  are  all 
given  one  name.  But  if  we  in  imagination  lengthen  our  life  so  that  we  wit- 
ness the  growth  of  a  river-system  as  we  now  watch  the  growth  of  plants,  we 
must  then  as  readily  perceive  and  as  little  confuse  the  several  physiographic 
kinds  of  lakes  as  we  now  distinguish  the  cotyledons,  the  leaves,  the  galls,  and 
the  flowers,  of  a  quickly  growing  annual  that  produces  all  these  forms  in 
appropriate  order  and  position  in  the  brief  course  of  a  single  summer. 

W.  M.  DAVIS. 
Cambridge,  Mass.,  September  7,  1887. 


Lakes  of  North  America. 


Plate  23. 


SKETCH    OF    PYRAMID    ISLAND,    PYRAMID    LAKE,    NEVADA. 


m  ' 


mn     III 


jAj  :       ly. 


r---^ 


I^-DEX. 


Abbott,  Humphreys  and,  Cited  on  rafts  in 

Red  river.  La.,  27. 
Abert  lake,  Oregon,  Analysis  of,  72. 

Origin  of,  30. 

Agassiz,  Lake,  Description  of,  103-106. 

Reference  to,  2. 

Aleutian  islands,  Lakes  on,  26. 

Algae,  Precipitation   of  lime  and  iron  by, 

76,  77. 
Alluvial  cones.  Obstruction  of  drainage  by,  6. 
Analysis  of  the  waters  of  alkaline  and  saline 

lakes.  Table  of,  72. 
Analysis  of  the  waters  of  fresh  lakes,  55-57. 

Great  Salt  lake,  by  E.  Waller,  81. 

Mono  lake,  by  T.  M.  Chatard,  88. 

St.  Lawrence  river,  by  T.  S.  Hunt,  60. 

Andrews,  E.,  Cited  on  erosion,  60. 
Annie,  Lake,  Cal.,  Origin  of,  10. 
Aqueous  agencies,  Lake  basins  due  to,  5-10. 
Areas  of  Laurentian  lakes,  58. 
Atmosijheric  agencies,  basins  due  to,  3-5. 
Au  Train  island,  Gravel  spit  on,  48. 

Bars,  Origin  of,  47,  48. 

Bear-wallows,  28. 

Beaver  dams.  Lakes  formed  by,  27. 

Belleville,    Ont.,    Height  of    ancient    beach 

at,  100. 
Bischof,  G.,  Cited  on  chemistry  of  water,  55. 
Bolsena,  Lago  di,  Ital.,  Mention  of,  20. 
Bonney,  T.  G.,  Cited  on  rock-basins,  41. 
Bonneville,  Lake,  Deltas  in,  50. 

Description  of,  106-109. 

Lakes  in  basin  of,  29. 

Overflow  of,  39. 

Borgne,  Lake,  La.,  Origin  of,  8. 
Bracciano,  Lago  di,  Ital.,  Mention  of,  20. 
Brienz,  Lake,  Switz.,  Reference  to,  7. 
Brigham,    A.   P.,    Cited    on    Finger    lakes, 

N.  Y.,  16. 
Buffalo,  X.  Y. ,  Rise  of  water  at,  39. 
Buffalo-wallows,  28. 


Calderas  or  crater-rings,  20. 

Canadian  river,  N.  M.,  Lava  flow  in  caiion 

of,  18. 
Carboniferous  lakes.  Brief  notice  of,  115. 
Cascades,  Basins  excavated  by,  5-6. 
Caspian  sea.  Brief  account  of,  69. 
Castani,  Lake,  Alaska,  Origin  of,  11. 
Catskill  Mts.,  Reference  to,  116. 
Cayuga,  Lake,  N.  Y.,  Origin  of,  16. 
Chaix  hills,  Alaska,  Lakes  near,  11,  12. 
Champlain,  Lake,  Terraced  borders  of,  92. 
Chatard,   T.   M.,   Analysis  of  the  water  of 

Mono  lake  by,  88. 

Cited  on  analysis  of  lake  water,  72. 

Chelan  City,  Wash.,  Mention  of,  66. 
Chelan,  Lake,  Wash.,  Description  of,  65-69. 
Chemical  action,  Basins  due  to,  31,  32. 
Chemistry    of    lake    waters,    55-60,    69-77, 

81-88. 
Chicago,  111.,  Rise  of  water  at,  34. 
Cinder  Cone,  Cal.,  Lakes  near,  18. 
Cleveland,  O.,  Erosion  near,  61. 
Climate,  Influence  of,  on  lakes,  37,  38. 
Climatic  conditions.  Relation  of,  to  lakes,  54. 
Coast  Survey,  U.  S.,  Charts  of,  9. 
Cochituate,  Lake,  Mass.,  Origin  of,  17. 
Color,  Pi-evailing,  of  lake  beds,  41. 
Columbia  river.  Wash.,  Lakes  in  old  channel 

of,  5,  6. 
Commerce  of  the  Laurentian  lakes,  61,  62. 
Como,  Lake,  Ital.,  Mention  of,  15,  <)4. 
Comstock,  C.  B.,  Cited  on  Lake  Survey,  57. 
Coon  butte,  Ariz.,  Description  of,  21,  22. 
Crater  lake.  Ore.,  Description  of,  20,  21. 

Mention  of,  64. 

Crater  lakes,  Origin  of,  19. 
Crosman,  C,  Records  of  erosion,  by,  60. 
Croton  river,  N.  Y.,  Soluble  matter  in,  56. 
Currents,  Waves  and,  in  lakes.  33,  34. 

Dana,  E.  S.,  Cited  on  thinolitic  tufa,  112. 
Dana,  Mt.,  Cal.,  View  from,  84,  85. 


122 


INDEX. 


Davis,  W.  M.,  Cited  on  classification  of 
lakes,  1,  117-120. 

Cited  on  crater  lakes,  19. 

Cited  on  lakes  of  Red  river,  8. 

CitecJ  on  lakes  retained  by  deltas,  7. 

Dawson,  J.  W.,  Cited  on  carboniferous  fos- 
sils, 115. 

Cited  on  Pleistocene  history  of  Lauren- 

tian  basin,  102. 

Dawson,  ^Y.  M.,  Cited  on  Lake  Yukon,  17. 

Delta  in  Lake  St.  Clair,  Origin  of,  40. 

Deltas,  Formation  and  structure  of,  48-51. 

Deltas,  Lakes  on,  8. 

Dendritic  tufa.  Origin  of,  110. 

Detroit  river.  Area,  water-shed,  etc.,  of,  58. 

Diastrophism,  Lakes  due  to,  28-31. 

Diatomaceous  earth,  Origin  of,  42. 

Dieulafait,  M.,  Cited  on  precipitation  of 
salts,  74. 

Diller,  J.  8.,  Cited  on  lakes  in  Cal.,  18. 

Dirt  glacier,  Alaska,  Lake  retained  by,  11. 

Drummond  lake,  Va.,  <  )rigm  of,  26. 

Dunes  retaining  lakes,  4. 

Dutton,  C.  E.,  Cited  on  Crater  lake.  Ore.,  20. 

Earthquakes,  Basins  due  to,  25,  26. 
Erie,  Lake,  Currents  in,  34. 

Effects  of  gale  on,  34. 

Erosion  of  the  shores  of,  61. 

Embankments,  Origm  of,  40-48. 
Erosion  of  lake  shores,  60. 

Fault-basins,  Description  of,  29,  30. 

Reference  to,  2. 

Finger  lakes,  N.  Y. ,  Origin  of,  1,6. 
Fisheries  of  the  Laurentian  lakes,  62. 
Florida,  Lakes  on  new  land  in,  1. 
Flow  of  streams,  Influence  of  lakes  on,  38,  39. 
Fort  Bidwell,  Cal.,  Lake  Annie,  near,  10. 
Fossils  in  sediments  of  lakes  Bonneville  and 
Lahontaii,  114. 

Gaylussite,    formation    of,    in    Soda    lakes, 

Nev.,  73,  74. 
Geneva,  Lake,  Switz.,  Delta  in,  91. 

Purity  of  water  in,  40. 

Gilbert,  G.   K.,   Cited  on  age  of  Great  Salt 

lake,  82. 

Cited  on  Coon  butte,  Ariz,,  21,  22,  24. 

Cited  on  ice-walls,  52,  53. 

Cited  on  Lake  Bonneville,  106. 


Gilbert,  G.  K.,  Cited  on  lake  in  Ice  Spring 
butte,  Utah,  19. 

Cited  on  lunar  craters,  24,  25. 

Cited  on  Pleistocene  history  of  Lauren- 
tian basin,  96. 

Cited  on  wind-erosion  basins,  3. 

Glacial  agencies,  Lakes  due  to,  10-17. 

Glaciers,  Lakes  on,  10,  11. 

Glen  Roy,  Scotland,  Ancient  beaches  in-,  12. 

Grand  Coulee,  Wash.,  Lakes  in,  5. 

Great  Basin,  Origin  of  lakes  in,  2. 

Pleistocene  lakes  of,  106-114. 

Great  lakes,  Pleistocene  history  of,  96-103. 

Great  Plain  of  the  Columbia,  lakes  on,  4,  5-6. 

Great  Salt  lake,  Utah,  Analysis  of,  72. 

Description  of,  77-83. 

Precipitation  of  sodium  sulphate  in,  75. 

See  also  Laurentian  lakes. 

Gustavila,  Lake,  Mex.,  Mention  of,  20. 

Gypsum,  Basins  due  to  solution  of,  32. 

Hamilton,  Ont.,  Height  of  ancient  beach 
at,  100. 

Hayden,  F.  V.,  Cited  on  Twin  lakes.  Col.,  14. 

Hayes,  C.  W.,  Cited  on  lakes  in  Alaska,  17. 

Hudson  river,  X.  Y.,  Soluble  matter  in,  56. 

Hull,  E.,  Cited  on  Laacher  See,  19. 

Humboldt  lake,  Nev.,  Analysis  of,  72. 

( )rigin  of,  10. 

Humphreys  and  Abbott,  Cited  on  rafts  in 
Red  river.  La.,  27. 

Hunt,  T.  S.,  Analysis  of  water  of  St.  Law- 
rence by,  00. 

Huron,  Lake,  Area,  depth,  etc.,  of,  58,  59. 

Currents  in,  34. 

Ice-built  walls.  Origin  of,  51-53. 
Ice  Spring  butte,  Utah,  Lake  in,  19. 
Inland  Salt  Co.,  Utah,  Operations  of,  82. 
Iroquois,  Lake,  Brief  account  of,  99. 

Judd,  .L  \y.,  Cited  on  Calderas,  20. 

King,  C,  Cited  on  Lake  Lahontan,  106. 

Cited  on  thinolite,  110. 

Klamath  lake.  Ore.,  Mention  of,  20. 
Krakatoa,  Eruption  of,  21. 

Laacher  See,  Germany.  Mention  of,  19. 
Lahontan,  Lake,  Nev.,  Description  of,  106- 
114. 


INDEX. 


123 


Lahontan,  Lakes  in  basin  of,  10,  29. 
Lake  Survey,  U.  S.,  Cliarts  of,  9,  48,  49. 

Tides  observed  by,  33. 

Work  of,  57,  58. 

Land  slides,  -Basin  formed  by,  31. 
Laurentian  basin,  Pleistocene  history  of,  90- 

103. 
Laurentian  lakes,  Account  of,  57- 

Areas  of,  58. 

Color  of  clays  in,  41. 

Currents  in,  33,  34. 

Erosion  of  the  shores  of,  60. 

See  also  Great  lakes. 

Lawson,  A.  C,  Cited  on  Pleistocene  history 

of  Laurentian  basin,  96,  100. 
Le  Conte,  Jolui,  Cited  on  Lake  Tahoe,  64. 
Observations  by,  in  Lake  Tahoe,  Cal. — 

Nev.,  35-37. 
Life  histories  of  lakes,  90-95. 
Lithoid  tufa.  Origin  of,  110. 
Lockyer,  N.,  Cited  on  meteoric  hypothesis, 

24. 
Loess,  Origin  of,  11. 
Logan,  Utah,  Delta  near,  50. 
Lonas  lake,  Lidia,  Description  of,  23. 
Lyell,  C,  Cited  on  rafts  in  Red  river.  La.,  27. 

Maggiore,  Lake,  Ital.,  Mention  of,  64. 

Reference  to,  15. 

Malaspina  glacier.  Lakes  near,  9,  11. 

Manitoba,  Lakes. in,  7. 

Manitou  island,  Lake  Michigan,  Sea  cliff  on, 
42. 

Mai-jelen  lake,  Switz.,  Origin  of,  11. 

Mechanical  sediments,  Deposition  of,  41. 

McGee,  W.  J.,  Cited  on  New  Madrid  earth- 
quake, 25. 

Meteoric  hypothesis,  Reference  to,  24. 

Meteors,  Basins  due  to  impact  of,  24,  25. 

Michigan,  Lake,  Area,  depth,  etc.,  of,  58,  59. 

Currents  in.  34. 

Effects  of  gale  on,  34. 

Erosion  of  the  shores  of,  60,  61. 

Influence  of,  on  climate,  38. 

Mississippi  delta,  "Mud  lumps"  on,  28. 

Mississippi  river.  Soluble  matter  in,  56. 

Mono  lake,  Cal.,  Analysis  of,  72,  88.  • 

Crater-lake  in,  19. 

Description  of,  83-89. 

Lake  on  islanrl  in.  24. 

Moraine  lakes  near,  14. 


Mono  Lake,  Cal.,  Recent  fault  near,  30. 

Tufa  bowl  near,  32. 

Moon,  Origin  of  craters  on,  24. 
Mora  river,  N.  M. ,  Luva  flow  in  canon  of,  18. 
Moses  lake.  Wash. ,  Origin  of,  4. 
Mountain  lakes,  Examples  of,  63-69. 
Muir,  J.,  Cited  on  lake   in  Stikine  valley, 
Alaska,  11. 

New  land  areas,  lakes  on,  1-3. 

New  Madrid  earthquake.  Lakes  formed  by, 

25. 
Niagara  i-iver.  Area,  water-shed,  etc. ,  of,  58. 
Newberry,   J.    S.,    Cited   on    lakes  in    coal 

swamps,  115. 

Oldham,  R.  D.,  Cited  on  Lonas  lake,  Ind.,  23. 
Ontario,  Lake,  Area,  depth,  etc.,  of,  58,  59. 

Currents  in,  34. 

Oolitic  sand,  Origin  of,  77. 
Organic  agencies.  Basins  due  to,  26-28. 
Owens  lake,  Cal.,  Analysis  of,  72. 
Ox-bow  lakes,  Origin  of,  8. 

Parks  of  Colorado,  Origin  of,  15. 
Peat  bogs.  Drainage  of,  42. 
Pepin,  Lake,  Origin  of,  7. 
Perkins,  E.  A.,  Cited  on  Seiches,  35. 
Playa  lakes,  Origin  of,  70,  71. 
Pleistocene  lake-beds,  Color  of,  41. 
Poe,  0.  M. ,  Lake  surveys  by,  58. 
Pontchartrain,  Lake,  La.,  Origin  of,  8. 
Powell,  J.  W.,  Cited  on  ob.structions  in  Colo- 
rado river,  7. 
Precipitates  from  saline  lakes,  71-77. 
Pyramid  lake,  Nev.,  Analysis  of,  72. 

Rain-fall  in  Laurentian  basin.  59. 
Ragtovvn,  Nev.,  Salts  formed  in  lakes  near, 
73. 

See  also  Soda  lakes. 

Ramsay,  A.  C,  Cited  on  rock-basins,  15. 
Red  river.  La.,  Lakes  on,  8. 

Timber  rafts  in,  27. 

Rhone,  Delta  of,  91. 

Rock-basins  made  by  glaciers,  13,  14. 

Rock-basins,  Origin  of,  4. 

Roth,  .1.^  Cited  on  chemistry  of  water,  55. 

Rothplitz,  A.,  Cited  on  oiilitic  .sand,  77. 

Rush,  Lake,  Utah,  Origin  of,  9,  10. 

Russell,  Thomas,  Cited  on  evaporation,  59. 


124 


INDEX. 


St.  Clair,  Lake,  Area,  water-shed,  etc.,  of, 

58. 

Delta  formed  in,  40. 

St.   Clair  river,  Area,  water'-shed,  etc.,  of, 

58. 
St.  Lawrence  basin,  Rain  fall  in,  59. 
St.  Lawrence  river.  Analysis  of,  60. 

Volume  of,  58. 

St.  Mary's  river.  Area,  water-shed,  etc.,  of, 

58. 
St.  Mary's  river.  Rise  of  water  in,  34,  39. 
Saline  lakes.  Description  of,  69-89. 
Sault  de   St.   Marie,  see  also  Saint  Mary's 

river. 

Vessels  passing,  61. 

Sandusky,  0.,  Lakelets  near,  28. 
Sea  cliffs.  Origin  of,  43^5. 
Sediments  in  lakes,  39,  40. 
Seneca  lake,  N.  Y.,  Deltas  in,  49,  50. 
Seiches,  Brief  account  of,  35. 
Sevier  lake,  L'tah,  Analysis  of,  72. 
Sink-holes,  Ponds  formed  in,  31. 
Smoke  creek  desert,  Nev.,  Lakes  on,  27,  28. 
Schermerhorn,  L.  Y.,  Cited  on  physical  feat- 
ures of  Laurentian  lakes,  68. 
Soda  lake,  Xev. ,  Analysis  of,  72. 

Origin  of,  19. 

See  also  Ragtown  ponds. 

Soap  lake,  Wash.,  Analysis  of,  72. 

Spencer,  J.  W.,  Cited  on  Pleistocene  history 

of  Laurentian  basin,  96,  102. 
Stevenson,  J.  J.,  Cited  on  lava  flow  in  New 

Mexico,  18. 

Cited  on  Twin  lake.s,  Col.,  14. 

Stikine  river,  Alaska,  Glacial  lake  in  valley 

of,  11. 
Stockton,  L'tah,  Small  lake  near,  9,  10. 
Stockton  bar,  Utah,  Brief  account  of,  10. 

Map  of,  12. 

Suez  Canal,  Commerce  of,  61. 

Superior,  Lake,  Ancient  beaches  on  shores 

of,  101. 

Area  of,  57. 

Area,  depth,  etc.,  of,  58,  59. 

Color  of  clays  in,  41. 

Currents  in,  34. 

Precipitous  shores  of,  45. 

Rise  of  water  in,  39. 

Sand  bars  on  shore  of,  48. 

Swallow-holes.  Ponds  formed  in,  31. 
Sweden,  Lake  ores  of,  77. 


Symons,  T.  W.,  Cited  on  the  Upper  Colum- 
bia, 68. 
Syracuse,  X.  Y.,  Salts  from  brines  of,  73. 

Tahoe,  Lake,  Cal.— Xev.,  Depth  of,  21. 

Description  of,  63-65. 

Mention  of,  67,  68. 

Temperature  of,  35-37. 

Tarr,  R.  S.,  Cited  on  Lake  Cayuga,  16. 

Taylor,  F.  B.,  Cited  on  delta  in  St.  Clair 
lake,   40. 

Cited  on  Pleistocene  history  of  Lauren- 
tian basin,  96-101. 

Temperature  of  deep  lakes,  35,  36. 

Lake  Tahoe,  64. 

Terraces,  Origin  of,  44-46. 

Tertiary  lakes.  Brief  notice  of,  115. 

Thinolite,  X'ature  of,  110. 

Thinolitic  tufa,  Origin  of,  110-113. 

Thun,  Lake,  Switz.,  Reference  to,  7. 

Tides  in  Laurentian  lakes,  33. 

Toledo,  0.,  Rise  of  water  at,  .34. 

Toronto,  Can.,  Height  of  ancient  beach  at, 
100. 

Topography  of  lake  shores,  43-49. 

Toulca,  Mt.,  Mex.,  Lake  in,  19. 

Toyatte  glacier,  Alaska,  Lake  retained  by, 
11. 

Truckee  river.  Obstructed  by  sand,  4. 

Tufa  in  Lahontan  basin,  110-114. 

Tulare,  Lake,  Cal.,  Origin  of,  6. 

Tundras,  Origin  of  lakes  on,  26. 

Twin  lakes.  Col.,  Origin  of,  14. 

Tyrroll,  J.  B.,  Cited  on  ice-walls,  52. 

U.  S.  Fish  Commission.  C^ted  on  fisheries  of 

Laurentian  lakes,  6. 
Upham,  Warren,  Cited  on  Lake  Agassiz,  7, 

104. 
Cited  on  lakes  Walden  and  Cochituate, 

17. 

Victoria  Nyanza,  Lake,  Area  of,  57. 
Volcanic  agencies.  Lakes  due  to,  17-24. 
Volcanic  dust.  Obstruction  of  drainage  by,  4. 

Wakatipu,  Lake.  X.  Z..  Origin  of,  15. 
Walden.  Lake,  Mass.,  Origin  of,  17. 
Walker  lake,  Xev..  Analysis  of.  72. 
Waller,  E.,  Analysis  of  water  of  Great  Salt 
lake  by,  81. 


INDEX. 


125 


Warren,  G.  K.,  Cited  on  Lake  Pepin,  7. 

Cited  on  outlet  of  Lake  Agassiz,  104. 

Warren,  River,  Source  of,  104. 
Watkins,  N.  Y. ,  Deltas  near,  49,  50. 
Waterto\\Ti,  X.  Y.,  Height  of  ancient  beach 

at,  100. 
Waves  and  currents  of  lakes,  33-39. 
Weather  Bureau,  U.  S. ,  Currents  in  Lauren- 

tian  lakes  observed  by,  33,  34. 
Weed,    W.    IL,    Cited   on    deposits  of    hot 

springs,  77. 
White,  A.  C,  Cited  on  ice-walls,  52. 


Wind-erosion  basins,  Origin  of,  3. 
Winchell,  A.,   Cited   on   isothermals  of   the 

Lake  Region,  38. 
Winnemucca  lake,  Nev.,   Analysis  of,  72. 
Winnipegasie,  Lake,  Ice-walls  of,  52. 

Yellowstone  park,  Precipitates  from  waters 

in,  76,  77. 
Yukon,  Lake,  Alaska,  Origin  of,  17,  18. 
Yukon  river,  Alaska,  Drift  timber  in,  27. 

Zuyder  Zee,  Origin  of,  8. 


This  book  is  DUE  on  the  last  date  stamped  below 


JAN  2  8  1937 


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